My Good Old Cessna 152
My Real US PPL
Sitting in my small PPL aircraft, the Cessna 152. Although it’s a long time ago ….. back to the summer of 2003, I struggled to fulfill my wish in getting my FAA PPL license and that within 28 days. Why did I mention 28 days? The reason is quite simple; my real MPH (Martinair Holland) ticket was only valid for 28 days.
Ok, you got that!
I flew to New Smyrna Beach, Florida (KEVB), where I had my lessons at IFT (International Flight Training). I believe this flight school doesn’t exist anymore, but the airfield isn’t changed much, at least, when I look to current photos, but I still keep my memories of the thunderstorms that build up during the midday and caused me many hours of trouble and not able to fly or not able to return to KEVB.
Anyway, this review – as of this writing June 2018 – is based on the recent released from Just Flight and Thranda Design, version 1.0. It is intended to be used with X-Plane 11.+.
The Real C152
The best way to find data about the real Cessna C152 is by using Wikipedia and, as far as possible, the Cessna company. So, let me see what information will be interesting for you.
Cessna took the venerable 150 and made some very significant changes to it in order to deal with the problems of bigger, heavier pilots and the unavailability of 80 octane fuel. The changes were so significant that Cessna introduced the upgraded aircraft under a new model number, the Cessna 152.
It was first delivered in 1977 as the 1978 model year, with the 152 as a modernization of the proven Cessna 150 design. The 152 was intended to compete with the new Beechcraft Skipper and Piper Tomahawk, both of which were introduced the same year. Additional design goals were to improve useful load through a gross weight increase to 1,670 lbs. (757 kg.), decrease internal and external noise levels and run better on the then newly introduced 100LL fuel (100 octane Low Lead).
As with the 150, the great majority of 152s were built at the Cessna factory in Wichita, Kansas, U.S.A. A number of aircraft were also built by Reims Aviation of France and given the designation F152/FA152.
Production of the 152 was ended in 1985 when Cessna ended production of all of their light aircraft. By that time, a total of 7,584 examples of the 152, including A152 and FA152 Aerobat aerobatic variants, had been built worldwide.
During my PPL lessons in Florida, KEVB (USA), I flew two different Cessna C152 models as can be seen on the screen shots below. These photo’s are just some examples of that’s available and even the cockpits could differ. For sure one thing was correct.
None of them have an Auto Pilot, and due to the aircraft weight, it was an unstable aircraft to fly. Any comparison with its bigger brother the C172, therefore was useless. I keep on remembering this cute, small aircraft as a nice airplane for learning to fly although new students quickly chose its bigger brother, the Cessna 172 instead of the many other brand models.
The 152’s airframe is an all-metal construction. It’s primarily Aluminum 2024-T3 alloy, although some components such as wing tips and fairings are made from fiberglass. The fuselage is a semi-monocoque structure. It has vertical bulkheads and frames joined by longerons which run the length of the fuselage. The metal skin of the aircraft is riveted, which allows loads to be spread out over the structure.
The wings are of a strut-braced design and have a 1-degree dihedral angle. The tapered (outboard) portion of each wing has one degree of washout (the chord of the tip section has one degree lower angle of attack than the chord at the end of the constant-width section). This allows greater aileron effectiveness during a stall, although it is much less than the 3 degrees used in Cessna 172 wings.
Dual controls are available as optional equipment on the Cessna 152 and almost all 152s have this option installed. The Cessna 152 is equipped with differential ailerons that move through 20 degrees upwards and 15 degrees downwards. It has modified Fowler (slotted, aft-traveling) flaps which are electrically operated and deploy to a maximum of 30 degrees.
The rudder can move 23 degrees to either side and is fitted with a ground adjustable trim tab. The elevators move up through 25 degrees and down through 18 degrees. An adjustable trim tab is installed in the right elevator and is controlled by a small wheel in the center of the control console. The trim tab moves 10 degrees up and 20 degrees down relative to the elevator chord line.
The Cessna 152 is equipped with a fixed tricycle landing gear.
The main gear is a tubular steel undercarriage leg surrounded by a full-length fairing with a step for access to the cabin. The main gear has 7 feet 7 inch (2.3 m) wheelbase. The nose wheel is connected to the engine mount and has an oleo strut to dampen and absorb normal operating loads. The nose wheel is steerable through 8 degrees either side of neutral and can caster under differential braking up to 30 degrees. It’s connected to the rudder pedals through a spring linkage.
The braking system consists of single disc brake assemblies fitted to the main undercarriage and operated by a hydraulic system. Brakes are operated by pushing on the top portion of the rudder pedals. It is possible to use differential braking when taxiing and this allows very tight turns to be made. The 152 is also fitted with a parking brake system.
It is applied by depressing both toe brakes and then pulling the “Park Brake” lever located to the pilot’s left. The toe brakes are then released but pressure is maintained in the system thereby leaving both brakes engaged.
There are hundreds of modifications available for the Cessna 152. The most frequently installed include the tail dragger conversions such as the ‘Texas Tail dragger’ conversion is available and have been fitted to some 152s. It involves strengthening the fuselage for the undercarriage being moved further forward, removing the nose wheel and strengthening the tail area for the tail wheel. This greatly improves short field performance and is claimed to give up to a 10 knot cruise speed increase.
Another modification is the STOL kit (Short Takeoff and Landing). The wings can be modified using a number of modification kits, some improving high speed/cruise performance but most concentrating on STOL performance. There’s so much more to explore on the Internet. This section is only a tip of the Cessna C152’s iceberg, but I hope it was informative enough.
Installation and Documentation
The installation of this Just Flight / Thranda Design aircraft is simple, straightforward and fast. Download the zip package from either Just Flight or in my case, via X-Plane.Org. Unzip the package and copy and paste folder “JF_C152” into the Aircraft folder. If you prefer another folder, feel free to make your own such as Aircraft/Just Flight sub folder. Since the product is serial number protected, a serial number has to be entered before the product can be used. Reload the aircraft once you’ve entered and validated.
This was the easiest part and if you want, you could fly now, but first, let’s highlight the DOCUMENTATION folder.
This folder contains the following documents and a sub folder:
– C152 X-Plane manual A4 150 (58 pages)
– C152 X-Plane ODM (Operating Data Manual) manual A4 150 (11 pages)
Both manual are worth the reading especially the 58 pages Operations Manual. It offers a lot of background informaion, aircraft systems information, a instrument panel description and operation and the panel selector. The “panel selector” (the white square with grey arrow on the left-hand side of your X-Plane screen) is an essential part of the feel, control and look of your C152. That said, it’s well explained in the manual and therefore there’s no need for me to do it again.
This manual also included a short tutorial that covers a UK flight UK. Although it’s a simple aircraft, it’s a good idea to have this flight included. At the end you’ll find the normal- and emergency procedures.
The ODM covers all kind of performances, mmore or less self-explanatory.
And last, but not least, a sub folder – JustFlight_C152_paint_kit – with all paint kit files in PSD format.
From a distance I see my nice, cute aircraft standing out there and waiting for me. Since it’s a small GA aircraft, it won’t take a long time to perform a walk-around check. On the other hand, I’m quite curious how this Just Flight model looks like, if it comes with many tiny details and does it have a weathered or used look!
I’ll start as usual at the nose of the aircraft, with the propeller. Remember, this model is new although the original model came from the Microsoft FSX platform, but for the rest, it’s all written or painted from scratch for X-Plane 11 (if I’m right). Besides that, we all know the Carenado C152II, but that aircraft officially stopped development for X-Plane 10.50 and yes, you could use it with X-Plane 11, but it’s too old and needed a new boost. That boost is now the Just Flight / Thranda Design C152!
Anyway, the first thing I see from a distance and believe me, it looks so realistic, is the implemented weathering. It looks so gorgeous! Everywhere I look and you will this do too, is weathering, dirty spots, oil drips, scratches and so on. I’m also aware that not everybody likes this, but I could be wrong and it could be that you’ve seen recently a brand new C152s, but the onces I’ve seen are all old, paint doesn’t look new anymore, many dents and/or scratches and so on. In other words, the way this C152 looks is quite realistic!
Ok, perhaps when you own yourself such a nice cute C152, you will keep it as new as possible, but the many I’ve seen flying around in the Netherlands and the USA, where old, dirty, full with dents and scratches and so on. Just like this JF C152!
Anyway, propeller blades look OK to me including the manufacture logo. The engine inlet gives you a good view of the air-cooled boxer engine as well as the engine cowling. You can’t remove the cowling to have a look inside, but the outside Aluminum covers with quick fasteners are nice and realistic.
Another well modeled piece is the Nose Landing Gear (NLG), but this is also applicable for the MLGs. Ok, landing gear is perhaps a bit too much, but each strut has full tiny details and, again, a lot of weathering is included. The pilot and passenger door can be activated via the panel selector poup window as well as that you’re able to activate / deactivate the straps, the nose wheel tow bar and the wheel chocks. All well made.
While walking from the nose section away, towards the left-hand wing leading edge, I can clearly see the air inlet for the inside mounted fresh air outlet, and a little further outboard you’ll find the pitot-tube and the STALL warning device. Oops, I couldn’t find the STALL warning device. I know it’s there, I know it should be there unless I’m totally wrong and that it’s mounted somewhere else!
Moving further along the leading edge to the wingtip, it seems there’s a lot of weathering. Too much? No, it feels good although some developers want to have a brand new looking model while others try to make it as realistic as possible. In this case, realistic keeping the “age” of the aircraft in mind. For me this looks moere then realsitic as possible. Well well done!
Yes, the C152 is equipped with a strobe light too, besides the old fashioned navigation lights. The white navigation light is mounted at the aft of the tail while the red anti-collision light is mounted on top of the vertical fin.
I lowered the flaps before starting with my walk-around although this is not always needed. They are looking good and I can’t see any misaligned parts. Before moving to the tail, I have a quick look at the main wheels. You can clearly see that the tire and wheel assembly are made with the help of photo-real material or perhaps it’s not photoreal material to texture it, but just handpainted. Whatever it is, it looks gorgeous.
I’m happy with the tail section too. No, honestly, I’m happy with the whole aircraft which is partly because of the weathering and that the latest X-Plane 11 features are included too.
What else near the tail section?
At the bottom the aft fuselage, I see the mooring hook and the mechanical linkages of the rudder control system. I’ll finish my walk-around inspection via the right-hand side, which will show the same things I’ve seen on the left hand as well as checking the overall quality. Before closing off my inspection, I’ll have a look at the upper wing surface with fuel caps.
I could write “my flight deck”, but that’s a bit too much for such a simple and old-fashioned cockpit, so just cockpit. Based on the high frame rates and, of course, depending on my Rendering settings, it’s not difficult to get 30, 40, of even more frame rates. As a good friend of mine is always saying … as long as everything goes smooth, you shouldn’t be interested in the actual frames and I agree with him. If I have 30, 40 or whatever frame rates, when scanning from left to right in the cockpit and all goes well thus without stutters or walking around the model on a complex airport, then it’s OK. Then there’s no need to worry. And there’s no reason to worry about the frames for this aircraft.
When you look around in this tiny cockpit, you’ll be surprised that two pilots can sit next to each other. I can tell you that if your instructor is not a thin person, there won’t be much space between each person. Tall people won’t have a pleasant stay in the C152 cockpit.
Anyway, the instrument panel, which is flown from the left-hand seat, offers only basic instruments like the altimeter, IAS indicator (Indicated Air Speed), turn and bank indicator, horizon, suction indicator, compass, an ordinary clock, VSI (Vertical Speed Indicator) indicator, ADF indicator, VOR indicator and the RPM indicator.
Somewhere in the middle you’ll find the ADF, VOR and ATC control panel. All basic, and it’s indeed nothing more then this. Although simple, it still looks good. You can, for clarity, temporarily remove the control wheel by clicking on the output shaft. Below the instrument panel in a different color you’ll find all the switches, knobs, engine controls, circuit breakers, all of which are working and let’s not forget the pitch trim (elevator) wheel.
And no, this aircraft doesn’t have a rudder or aileron trim. In this lower instrument section, you’ll also find the ENGINE OIL TEMP and FUEL QUANTITY indicators and the elevator (pitch) trim.
Moving on, all sidewalls, ceiling, floor and rudder pedals are accurately modeled. I almost forgot to mention the two air outlet controls, located at the left and right edges of the windshield near the wing structure. The left-hand control tube can be pulled out and rotated for fresh air while the right hand one also has a temperate gauge built in. Via the panel selector popup upper row, 3rd icon from the left, you can request the Garmin GNS430, for those who want this navigation equipment. More about this GNS430 later.
And what about the virtual cabin?
That’s quite simple and straightforward. The baggage area can only be reached from the inside by throwing your stuff over your seat. There’s no external baggage door available, but what I see, feel good and realistic.
For the evening and night flights, you’ve got a light control rheostat. The inner knob is used for the integral lighting of the radio and navigation control panels. The outer rheostat knob is used for all other instrument lighting. Then there’s a cockpit instrument panel floor light switch on the lower left-hand section and finally, a ceiling switch for lighting the cabin or the seats and baggage area behind. Unless I missed it, but in my PPL C152 I also had a red night light which I couldn’t find in this modeled C52. Not an issue at all since it could be that it’s not avaialble in every C152.
After all, I’m very satisfied with the overall modelling.
My Floridian cross-country
I think it’s a good idea to reproduce one of my real favorite flights from KEVB (New Smyrna Beach) to KCDK (Cedar Key). It won’t be a flight as it was in real since I’m not sure how accurate the Florida default scenery is beneath me, but with the help of ortho textures from ZonePhoto it should work out fine.
I’ve planned a morning flight, and using real weather. The cross-country flight goes from KEVB (New Smyrna Beach), passing south of KDED (Deland-Taylor), along Leesburg Regional (KLEE), then on a heading for VORTAC OCALA (113.70 KOCF) and then straight on a heading of approximately 270 to Cedar Keys National Wildlife Refuge. Just East of it is the George T. Lewis airport (KCDK). From Ocala it’s, when we’ve left the Floridian country behind us, it’s only a swamp, so I must try to stay in the air.
Starting from left to right screenshot, I depart from KEVB, runway 29, which due to no wind conditions, is the closest to the apron. On a heading of 270 degrees I fly towards De Land-Taylor airport. From De Land-Taylor I climb as quickly as possible to a higher altitude before flying towards Lake Yale and Leesburg (KLEE).
Before approaching Leesburg, it’s time to tune to VORTAC OCALA.
I fly on a heading of 270 degrees towards and along the coastline to Cedar Key over a swamp. I hope nothing happens and just in case, I’m flying over the swamp at 4,000 feet. In that case, I’ve enough altitude to descend to a safe area outside the swamp. Another advantage of this high altitude is the great view.
I’ve done all my preparations, and ready to go. Since KEVB is an uncontrolled airport and therefore no TAF available, I use the one from KDAB (Daytona Beach International) but it seems there’s hardly any wind, so I can choose from one of the eight runways and since I’m alone at KEVB, I decide to take off from 29, which is the closest to reach.
Engine running, checks performed, I finally taxi to holding point for runway 29. Flaps set, and before turning onto the runway, I listen once more to the radio to check if suddenly somebody decides to land on 29. Full power and there I go .. me and my C152. At around 70 knots I pull slightly on the yoke and she’s airborne. By the way, it lokos like that a kind of rumbling noise is introduced. This is something I noticed during the takeoff roll. Although I used the default KEVB airport, I know for sure that no center lights are included in the default scenery, so it must be something that is added in the model. Nice but above all, realistic sound.
I’ll stay at roughly 1,000 feet for a while because I’m not interested in getting in contact with Daytona Beach, which is a Class C airport. I’m currently flying on a heading of 270 and that should bring me straight to De Land-Taylor airport.
If you look at the Jacksonville Sectional Chart in front of you, you’ll see two highways. The moment I pass this intersection, I can climb to 4,000 feet or higher.
Since there’s no Auto Pilot in this C152, it’s important that once you’re at your cruising altitude, you trim the aircraft. What I mentioned before, official trimming for the C152 is only possible for pitch while the modeled aircraft and perhaps a basic X-Plane 11 behavior, allows you also to trim for roll.
That said, it’s an easy aircraft to fly and if you want to go to the basics of flying, then this is a great choice. Oops, I should watch out for the prohibited areas on my right and I can see the city of Orlando and KCMO far away on my left. And easy to see from this distance is Lake Apopka.
With so much time available for myself, I’ve selected Ocala VORTAC (113.70). When I’m close to Leesburg Regional, I make a gentle turn to acquire the VOR and fly straight to Ocala. With these weather conditions and the external view, it’s not difficult to pinpoint Ocala City.
In-between this stretch I have some time to check out the C152 flight dynamics like slow flights, pre-stall conditions and some steep turns although the steep turns could also be done near my destination outside the swamp.
I’m approaching Ocala and arrive west of the city and yes, I can see the airport from 4,000 feet. This is the right moment to turn to a heading of 270. From now on to my destination airfield, I’m not planning to do any tricks or whatever would put me in danger.
Remember, most of the land below are swamps and I don’t want to sit next to an alligator! This last part to Cedar key is a pure flight under Visual Flight Rules thus VFR conditions. There’s no longer an NDB or VOR beacon in the vicinity, so it’s just me and my eyes and the ortho ground textures from Zones Photo scenery although ity must be said that these square looking edge textures don’t look very realistic, but OK, I need to accept it.
My flight is reaching the end and I must say that I’m very happy with the C152. It feels like the good old days of my PPL lessons are popping up again. Although the C152 is a less stable aircraft compared to the C172, it’s so much fun to fly this Just Flight/Thranda Design C152.
I’m approaching the Cedar Keys National Wildlife Refuge and this looks slightly different then I remember from the real flights. While still flying at an altitude of 4,000 feet, it’s time to descend to at least 1,000 feet. Circling on the way down helps and before I know it, I’m at a more decent altitude to make my landing.
The runway at Cedar Key isn’t very long and on both sides, there’s water all over, all around it, so I have to watch out and brake at the right moment. But first I need to land at the right spot on the runway.
I liked this.
I liked it very much!
I felt in love “again” with this dedicated X-Plane 11 C152 from Just Flight/Thranda Design.
Suppose I use the popup GNS430
It could be an option, right … using the popup Garmin GNS 430.
Using this add-on default X-Plane 11 GNS 430 navigation device could be an interesting option. It’s included in the model, but just to make clear, it’s not integrated in the instrument panel. I think, just a thought, it’s these days a mandatory piece of equipment having it on board. Not installed, but as a seperate device, right?
That said, let’s see how and where to create “fms” flight plans.
Creating a Flight Plan
To create a flight plan you could use many programs, but let me highlight a couple of freeware possibilities. Let me start with Routefinder which offers you quickly a flight plan, but this is not in “X-Plane fms” format. If you don’t like Routefinder, you could check out FlightAware, but again, this doesn’t allow you to export it to an fms file format; however, it offers real flight plans.
Another very interesting website is simBrief. Register for free and a wealth of flight planning information becomes available. It should be noted that simBrief prefers that you have a Navigraph account else it will use the data from RouteFinder.
Then there’s the browser-based Online Flight Planner (http://onlineflightplanner.org) which seems to be a good one although I’m not 100 percent sure if the generated flight plans are as real as they should be. The good news is that it seems to do the same as RouteFinder, but with several export options, of which one is “X-Plane fms”.
One more option but that requires two steps is using SkyVector and X-PlaneTools. We all know SkyVector, but SkyVector saves your flight plan in fpl format which in turn can be converted to fms with X-PlaneTools.
By the way, when you insist on using RouteFinder or FlightAware, you can use the same X-PlaneTools website also for converting these flight plan extension to a “fms” extension. Anyway, copy the created fms file into the X-Plane root folder Output/FMS plans. With the fms file in this folder, you’re able to load the flight plan into the Garmin GNS 430.
You can also go for the offline freeware tool LittleNavMap, but it can do much more then just flight planning. Besides many other things, this is a great tool in case you need to create flight plans with any type of flight plan extension.
What’s the advantage of a Flight Plan?
Compared to the previous VFR flight, the same flight under IFR conditions would have, in combination with the Garmin GNS430, a lot of advantages. The previous VFR flight is besides only VORTAC beacon that is included, only based on visual means. Visual means by following roads, passing lakes, following shorelines and so on. When you do the same flight by using the GNS430, you follow the waypoints that are included and you never fly in the wrong way and you always bypass (flying around) restricted areas since you made the flight plan in this way.
When the C152 had an Auto Pilot, then it was even much easier, but ok, we have to follow the route as indicated on the GNS430 by hand. By hand means with this C52 that you do the same as under VFR conditions, but in this case you follwo the flight plan on the GNS430 and keep on monitoring your roll and pitch.
By the way; the flight plan I created with Little NavMap contains the following waypoints; KEVB – SMYRA – LAMMA – YEBBU – SEVAE – OXAGE – MODIN – OCF (VORTAC) – KOYEC – CEDDI – KCDK.
The above screenshots don’t cover the same flight again, but do give you an idea when you have the GNS430 in view, that following the flight path on its display is easy and straightforward. The screenshots are taken just after takeoff while climbing out to 1000 feet, and passing the first waypoint SMYRA.
As far as I can see in the Sounds folder, only 916 Kb, that all sounds are to my humble opinion not dedicated for the C152.
I think I covered most of it, but there’s always a chance I missed things. Although it’s a simple aircraft with a minimum of instruments, you can easily forget something.
Perhaps some additional words about frame rates?
I mentioned this already before … the Just Flight/Thranda Design C152 is a frame rate friendly aircraft and although I can’t speak for every PC or Mac out there, I think nobody should get any problems to produce reasonable frame rates. You and I, we’re all aware that the actual frame rates depend not only on your hardware, but also on your X-Plane settings. But overall, with a complex environmental system active, arriving or departing from a complex airport and having your rendering settings at high, it still should give frame rates starting between 25-30, but most likely higher.
The above FPS (Frame Rates per Second) screenshots are taken with additionally installed FlyTampa Corfu Airport/Island and the FlyWithLua Environment+ 1.1 script. Further on, I used real weather and real time.
I had the intention to write a quick impression, then I decided to write a medium length review, but at the end it turned out to be a comprehensive review. I think, if you’ve enjoyed the review, you’ll know why. Since my real PPL lessons are a long time ago, I can’t judge for the fully 100 percent if it flies as real as it gets. I had the idea, during my PPL lessons, that the C152 was a bit more unstable then how this modeled C152 flies.
I can remember that I constantly needed to correct the pitch and roll. At some parts of my simulated cross-country trip There where moment I didn’t need to do anything. Ok, it could be that the C152 I flew wasn’t 00 percent or that the environmental conditions are different then what I have in mind and how X-Plane acts.
Thus, the question is, is it worth acquiring this modeled C152?
The answer is YES, without doubt! Worth being a member of your GA aircraft collection. The package comes, I didn’t mention that before, with a couple of liveries and high quality PSD files for those who want to paint additional liveries. As of this writing, June 17th 2018, I haven’t seen yet user liveries for this aircraft, but that can come. Hopefully it will. and yes, it should be noted that the model is only compatible with X-Plane 11.
I’m aware that there’s something else out there, in particular for those simmers who own the Carenado C152 II version 3.2 for X-Plane 10.x. I know that the following has nothing to do with this review, but at the same time I think it’s fair to highlight that option briefly, so let me highlight this briefly. X-Plane.Org user “nhadrian” created an package, I assume with the agreement of Carenado, that makes the Carenado C152 II compatible with X-Plane 11.
Where can you buy the Just Flight / Thranda Design C152 package?
I got it via X-Plane.Org, but it’s also possible to buy it via the Just Flight website. The dedicated X-Plane.Org web page can be found via this link. As of today, June 2018, the price of this product is 41.99 USD. This review is based on JF product version 1.0, with X-Plane version 11.21.
For this review, I used besides the payware Just Flight / Thranda Design C152, the following payware and freeware add-on sceneries:
– Freeware | Zones Photo Florida
– Freeware | Andras Fabian alpilotx.net HD Mesh Scenery v4
– Freeware | FlyWithLua 2.6.7 for X-Plane 11
– Freeware | Environment + 1.1
– Freeware | Little NavMap
Angelique van Campen
|Add-on:||Payware Just Flight Cessna C152|
|Publisher | Developer:||X-Plane.Org | Just Flight|
|Description:||Realistic rendition of the Cessna C152|
|Software Source / Size:||Download / Approximately 1.17GB (unzipped)|
|Reviewed by:||Angelique van Campen|
|Published:||June 19th 2018|
|Hardware specifications:||- iMac Pro|
|- Intel 3GHz Intel Xeon W / 4.5Ghz|
|- Radeon Pro Vega 64 16368 MB|
|- 64 GB 2666 MHz DDR4|
|- 1 internal 1TB SSD (High Sierra 10.13.4)|
|- Saitek Pro Flight System X-52 Pro and X-56 Rhino|
|Software specifications:||- High Sierra (10.13.4)|
|- X-Plane 11.21|