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Pumpkin drop event

FT-22... On Steroids

BATTLEAXE

Well-known member
#1
I have a craving for a Hot Rod in the fleet and it is going to be way of the FT-22. I am in need of a pusher and this might fit the bill. Plus there has been some decent talk up about this plane and it has my curiosity peaked. It will be the second airframe I build running on elevons, the first being the Mini Arrow, which didn't last long but that was back in the day when I had no clue how to fly. Now that the skills are honed in some I want to step up the caliber of this little monster in the making. The FT-22 is based of an A or F pack and I want to take it up a notch, or a few. This is C pack bound and, as per usual, heavily modified to accommodate.

I know what some will say, "You should build it stock and fly that first and then modify gradually". That's not how I roll, any of you who know my builds knows that I don't do stock anymore. Plus I like to have fun fiddling with the design, and as far as flying the stock bird I have a partner in crime who has plenty of experience with the stock model and is willing to do his V4 on this thread so we will see where this ends up. This friend is none other then @The Hangar himself, has built 3 of these and has convinced me to give it a shot... WHY NOT!

Starting out as always it is advisable to print out the plans and give yourself a base to start from. I usually go with the tiled plans on any build and tape them together to get my lay out, this was no different. However the tiled specific plans came without alignment cut marks in the corners to get the sheets straight, no problem, seen this before. In dealing with it, trying to line up the black cut lines to puzzle this together. it took forever to get 5 sheets to come together then trying to get the rest to coincide was like herding cats. Scratch that. They must be old plans that have been swept to the side. All kudos to Sponz who usually works his CAD magic but I wasn't gonna waste all night trying to figure this out when I could go at this from another direction. I downloaded the full size plans and tiled them in Adobe Acrobat... life hack #273. everything fit like a charm, used more paper, (30 instead of 17), but so worth the effort.
FT-22 plans.jpg
Plans assembled and ready for the designing pencil. Here are some of the mods I am planning:
1. C Pack as mentioned before, will require a stronger fuse, which will extend all the way back to the motor mount top and bottom
2. the battery hatch on top will be extended back as well to make room for lots of fore and aft movement of the battery for CG
3. removable nose much like the Explorer or Bronco to take hits without destroying the airframe and is easily replacable
4. a plywood spar on edge will run completely through the wings
5. moving the servos back to shorten the push rods, and the kicker which may warrant some attention and advice from others...
6. a KFM wing design, this will be up for discussion among others to see if I can get this to fly on an airfoil design instead of just using the Bernoulli principle to maintain altitude. @The Hangar tells me he likes to fly his tail heavy which has me thinking the high AOA makes this plane easier to fly. Straight and level is what i am looking for so I am going to experiment with this idea.

Anyone else wants to join in whether you want a stock FT-22 or a modified version of your own design, or even copy either of ours is totally welcome to jump on this thread and post their progress as well. This should be a decently quick build and I really look forward to what the results end up being, if it doesn't work... it's just foam board.

Thanks for reading
 

The Hangar

Well-known member
#2
Woohoo - I’m pumped for this! I’ll just put a list of the mods I want to do on this beautiful bird!
1) rudder. I’m not quite sure how I’m going to work it out yet, but this is something that will be fun to experiment with.
2) landing gear. I’m not sure if I’ll be able to pull this one off, but I’m going to give it a shot...
3) better control surfaces. Bigger = better and I have a hinge trick up my sleeve😁
4) nose. The stock nose looks cool, but v4 will have the best looking nose ever found on any rc f-22 - or real one for that matter! Just kidding 😂
5) last but not least, a sweet paint job to make it look like a real f-22! Believe it or not, I haven’t painted any of the previous ft-22s, so this will be a first.

I’ll also be adding some wooden strength braces through the fuse and a spar on the wing. I’ll also be moving the servos back. I can’t wait to get started in this!
 

BATTLEAXE

Well-known member
#3
I did some googling last night and picked up a couple 3 view renderings of the F-22 that I am going to try to emulate as far as profile of the plane. If this plane works out with all the mods I will be doing to it I will try to go for another FT-22 that has more likeness to the F-22, except for the big prop hacked through the center of coarse lol:
F-22 3 view 1.jpg
F-22 3 view 2.jpg I guess the last one is more of a 4 view. Looking at these pictures if I was to do a second one, would have the tapered under side for the air intake tubes, inline with the angle of the Vstabs. I like the idea of the scale paint job that @The Hangar is looking to do.

In looking at these pics I am seeing the rear landing gear is significantly further back then the intended CG on the model. This has me thinking since this is somewhat of a delta wing it has a pretty forgiving CG point, just a guess though. I'll be able to play with that at the field once flying it.

Thanks for reading
 

The Hangar

Well-known member
#4
Haha - after seeing those pics, I’m starting to think about v5 as well. So scrap the landing gear idea - with the prop being a 9 inch, it sticks so far down that you’d have to have some pretty long and flimsy wire, as v-5 will be an edf(s) I won’t have to worry about prop clearance...
 

BATTLEAXE

Well-known member
#5
Haha - after seeing those pics, I’m starting to think about v5 as well. So scrap the landing gear idea - with the prop being a 9 inch, it sticks so far down that you’d have to have some pretty long and flimsy wire, as v-5 will be an edf(s) I won’t have to worry about prop clearance...
If you look at the 3 views with the landing gear, to scale the rear wheels are well behind the intended placement of the prop on the model, so I am thinking if you locate the landing gear in the same spot it may protect the prop more then not having landing gear... just a thought. Makes me curious as to how it will rotate on take off being its a pusher, whether the prop being slightly above the wing would want to push the plane to the ground instead... might make for a long take off distance. Hard to speculate. Might be questions for @Hai-Lee to answer, fire up the bat signal!
 

L Edge

Well-known member
#6
If you look at the 3 views with the landing gear, to scale the rear wheels are well behind the intended placement of the prop on the model, so I am thinking if you locate the landing gear in the same spot it may protect the prop more then not having landing gear... just a thought. Makes me curious as to how it will rotate on take off being its a pusher, whether the prop being slightly above the wing would want to push the plane to the ground instead... might make for a long take off distance. Hard to speculate. Might be questions for @Hai-Lee to answer, fire up the bat signal!
 

The Hangar

Well-known member
#7
If you look at the 3 views with the landing gear, to scale the rear wheels are well behind the intended placement of the prop on the model, so I am thinking if you locate the landing gear in the same spot it may protect the prop more then not having landing gear... just a thought. Makes me curious as to how it will rotate on take off being its a pusher, whether the prop being slightly above the wing would want to push the plane to the ground instead... might make for a long take off distance. Hard to speculate. Might be questions for @Hai-Lee to answer, fire up the bat signal!
Hmmm... I fly off grass usually so my prop is pretty safe. I do think it would look cool and scale so I can go to the dirt baseball field field if needed for planes with landing gear. I’m not sure if I’ll just go ahead ahead and use the elements simple firewall, or if I’ll figure out a way to keep my c pack useable in my spitfire and ft-22. I can fly my spitfire off my b pack if needed though. If I do use my swappable power pod, I’ll put it a little lower so the thrust is in line with the control surfaces.
 

The Hangar

Well-known member
#8
On edf v5, I’ll be mounting the edf below the wing, so she might want to pitch up upon take off. I also want to add a thrust vectoring system similar to what @Headbang is doing on his viggen... you can see what I’m talking about if you look at the ft vector jet - except this will all be internal. It’ll help with high alpha a lot.
 

L Edge

Well-known member
#9
The easy way to insure a short liftoff is to have the nosewheel higher than the main gear. I spent a number of months designing gear to fly off grass. The clumps of grass are a PITA for steering and finally resolved the issue by designing the nose wheel coming straight down2/3 way and then back 45 degrees reinforced with a 45 degree wire on the gear back to fuse.
The main gear is always put right under my carbon wing re-enforced rod and doesn't budge when it comes in hard.

Since the battery is usually in the nose, it handles all those hard landings on my F-22.
 

L Edge

Well-known member
#10
On edf v5, I’ll be mounting the edf below the wing, so she might want to pitch up upon take off. I also want to add a thrust vectoring system similar to what @Headbang is doing on his viggen... you can see what I’m talking about if you look at the ft vector jet - except this will all be internal. It’ll help with high alpha a lot.
Try it with moving canards as well as TV and it really changes the way it flys.
 

BATTLEAXE

Well-known member
#11
The easy way to insure a short liftoff is to have the nosewheel higher than the main gear. I spent a number of months designing gear to fly off grass. The clumps of grass are a PITA for steering and finally resolved the issue by designing the nose wheel coming straight down2/3 way and then back 45 degrees reinforced with a 45 degree wire on the gear back to fuse.
The main gear is always put right under my carbon wing re-enforced rod and doesn't budge when it comes in hard.

Since the battery is usually in the nose, it handles all those hard landings on my F-22.
Do you have any pics of your landing gear on a FT-22.
Try it with moving canards as well as TV and it really changes the way it flys.
Canards you say... not fixed like on the viggen but live ones. What would be the best servo linkages to use without 3D printing
 

BATTLEAXE

Well-known member
#12
Got back from the big city and came with presents: 20190920_131910.jpg
All loaded up on FB for this project and another Scout. Man I love FB, so cheap to buy and effective to build with.
20190920_131929.jpg
Got some glue sticks... though I am kinda worried about my choice in the type of glue sticks. Can you tell the difference in the new ones from the old ones?
 

L Edge

Well-known member
#13
This one has taken a beating due to work on automated leading edge flaps.

IMG_0243.JPG

Main gear over the carbon rod.

IMG_0244.JPG

Feel free to use or modify. Handles any type of grass.

Another mod I did was add nose steering for the F-22 by a servo if you only have elevons. Hard to steer without it until airspeed is enough that rudder can handle it. Also added balsa 2 1/2' strip from nose to motor mount to stiffen whole unit.

This is why it got that way, not recovering.
 
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BATTLEAXE

Well-known member
#14
This one has taken a beating due to work on automated leading edge flaps.

View attachment 143075

Main gear over the carbon rod.

View attachment 143076

Feel free to use or modify. Handles any type of grass.

Another mod I did was add nose steering for the F-22 by a servo if you only have elevons. Hard to steer without it until airspeed is enough that rudder can handle it.
Are those 2" wheels?

This landing gear idea has got the creative wheels turning... no pun intended lol.

If I get this first one flying with great results then I will build a second which will have landing gear. I have never done take offs with tricycle style and I like the fact you can do steerable with a third servo.

Thx @L Edge
 

Hai-Lee

Old and Bold RC PILOT
#15
If you look at the 3 views with the landing gear, to scale the rear wheels are well behind the intended placement of the prop on the model, so I am thinking if you locate the landing gear in the same spot it may protect the prop more then not having landing gear... just a thought. Makes me curious as to how it will rotate on take off being its a pusher, whether the prop being slightly above the wing would want to push the plane to the ground instead... might make for a long take off distance. Hard to speculate. Might be questions for @Hai-Lee to answer, fire up the bat signal!
Normally you can determine the effect upon the airframe by determining the planes centre of mass and then the motor thrust line. Where these are parallel you can look at the vertical separation and calculate the resultant rotational force, (nose up or nose down force). Normally in a Prop/Slot the motor can be quite a significant distance from the centre of mass as the thrust/propwash flows over the control surfaces and actually provides more than enough surface control to overcome the rather minuscule nose up/down pitching forces.

When looking to improve ground clearance on a prop/slot, (in this case with a 9 inch prop), I would increase the blade count and reduce the diameter. For the same pitch I would use a 8 inch 3 blade or even a 4 blade 7 inch prop.

Have fun!
 

BATTLEAXE

Well-known member
#16
Normally you can determine the effect upon the airframe by determining the planes centre of mass and then the motor thrust line. Where these are parallel you can look at the vertical separation and calculate the resultant rotational force, (nose up or nose down force). Normally in a Prop/Slot the motor can be quite a significant distance from the centre of mass as the thrust/propwash flows over the control surfaces and actually provides more than enough surface control to overcome the rather minuscule nose up/down pitching forces.

When looking to improve ground clearance on a prop/slot, (in this case with a 9 inch prop), I would increase the blade count and reduce the diameter. For the same pitch I would use a 8 inch 3 blade or even a 4 blade 7 inch prop.

Have fun!
Good point on the prop clearances, makes a lot of sense.

What about a KFM wing on this plane, any thoughts to that one?
 
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BATTLEAXE

Well-known member
#17
I was thinking of doing a KFM2 with one extra layer and a spar out of BBQ skewer, laid out like this: 20190920_140257.jpg
The art line starting just behind the prop would be the TE of the top layer accounting for 50% of the wing surface or chord, including the elevons as part of the wing. The LE of the top layer would start behind the inlets just in front of the back of the fuse cut back indicated by the lines drawn in. Thoughts...
 

Hai-Lee

Old and Bold RC PILOT
#18
I was thinking of doing a KFM2 with one extra layer and a spar out of BBQ skewer, laid out like this: View attachment 143083
The art line starting just behind the prop would be the TE of the top layer accounting for 50% of the wing surface or chord, including the elevons as part of the wing. The LE of the top layer would start behind the inlets just in front of the back of the fuse cut back indicated by the lines drawn in. Thoughts...
KFM will provide an increase in lift and strength but it will also increase the weight, prop noise, and drag!

If you do add a second layer make it the foam only initially. It will fly but if you are really going for speed KFM will not help much! Drage could be reduced slightly by bevelling the LE and TE on the top layer but it can ba a lot of work for a minute gain!

Have fun!
 

BATTLEAXE

Well-known member
#19
KFM will provide an increase in lift and strength but it will also increase the weight, prop noise, and drag!

If you do add a second layer make it the foam only initially. It will fly but if you are really going for speed KFM will not help much! Drage could be reduced slightly by bevelling the LE and TE on the top layer but it can ba a lot of work for a minute gain!

Have fun!
Got ya. I am going to try it. I will iron the edges as well. the airframe is generally light compared to others I have built. All that is left to do is build it and see what happens. Thank you for the insight
 

The Hangar

Well-known member
#20
Got back from the big city and came with presents: View attachment 143077
All loaded up on FB for this project and another Scout. Man I love FB, so cheap to buy and effective to build with.
View attachment 143078
Got some glue sticks... though I am kinda worried about my choice in the type of glue sticks. Can you tell the difference in the new ones from the old ones?
I just use the super cheap Adtech sticks from Wally world... Like the two tall light ones you got