FlyCat 90 video
03-07-2010, 11:14 PM
#1
FlyCat 90 video
http://www.youtube.com/watch?v=eYAsK4dlwaM
Hi,.... so I got this plane put together and have made a video of it flying . Engine is a SuperTigre 90 turning an APC 13x6 pusher prop, no retracts , just the stock landing gear wire that is way too soft! The nose gear wire wooden former broke on this plane even before it had its maiden flight, I fixed that by epoxing a piece of 3/8 aircraft ply to the broken former and mounted the nose gear bearing to the new ply piece. The fiberglass on the fuse is exceptionally too thin and has already split and cracked and the paint has chipped off on several places.
DO NOT try and fly the plane at the listed cg of 12 inches measured from the leading edge of the wing,
that's stated in the manual..... YOU WILL CRASH due to the plane being tail heavy! I have the cg at 10 inches.
ATTN: NitroModels...PLEASE CORRECT THE CG TO 10' IN THE INSTRUCTION BOOKLET.
Also, I have the rear of the fuel tank even with the cg, which the REAR of the tank is located even with my cg mark.
Also, the instructions have you place the fuel tank at inside of the plane right up to the firewall,...
think about that...this is just going to make a bad rearward cg problem even WORSE once you fil the tank with fuel.
Even with the SuperTigre 90 2 stroke turning the prop at 11,900 rpms today, the plane is no faster than a standard 46 size plane.
I am disappointed in its speed, or I should say, lack of speed. It looks like it should be a rocket, but its just not there.
Just my .02 worth.
John
Hi,.... so I got this plane put together and have made a video of it flying . Engine is a SuperTigre 90 turning an APC 13x6 pusher prop, no retracts , just the stock landing gear wire that is way too soft! The nose gear wire wooden former broke on this plane even before it had its maiden flight, I fixed that by epoxing a piece of 3/8 aircraft ply to the broken former and mounted the nose gear bearing to the new ply piece. The fiberglass on the fuse is exceptionally too thin and has already split and cracked and the paint has chipped off on several places.
DO NOT try and fly the plane at the listed cg of 12 inches measured from the leading edge of the wing,
that's stated in the manual..... YOU WILL CRASH due to the plane being tail heavy! I have the cg at 10 inches.
ATTN: NitroModels...PLEASE CORRECT THE CG TO 10' IN THE INSTRUCTION BOOKLET.
Also, I have the rear of the fuel tank even with the cg, which the REAR of the tank is located even with my cg mark.
Also, the instructions have you place the fuel tank at inside of the plane right up to the firewall,...
think about that...this is just going to make a bad rearward cg problem even WORSE once you fil the tank with fuel.
Even with the SuperTigre 90 2 stroke turning the prop at 11,900 rpms today, the plane is no faster than a standard 46 size plane.
I am disappointed in its speed, or I should say, lack of speed. It looks like it should be a rocket, but its just not there.
Just my .02 worth.
John
03-08-2010, 12:35 PM
#2
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RE: FlyCat 90 video
Sounds like you are new to Pusher prop planes....
Pusher prop planes really need to have their C.G. adjusted and set with the tank FULL.
If not the plane will be far too tail heavy and the stated problems will appear.
Setting the C.G. with the tank empty gives erroneous and potentially dangerous results.
If you set the C.G. with the tank full, the indicated C.G. is fine.
Also: You are not getting a lot of speed out of the plane because your engine is too loaded down by the prop.
I fly a GMS .76 with mine ( both on this plane and my Bobcat 50 ).
The plane flies much like any other tractor plane of similiar size when I use a recommended prop, as you have appeared to have done.
I swapped my prop out for an 11x8 Graupner pusher prop, which is considerably undersized for the engine I used, but provides more pitch.
This reduces the overall thrust in exchange for speed.
My plane is fairly fast this way, turns MUCH higher RPM's, and has plenty of verticle thrust due to the larger engine used.
Your engine is still maintaining low to standard RPM's, so it will not get the plane any faster than what you are seeing now.
For more speed adjust the prop instead. It - MUST - unload in the air and you need a higher pitch.
e.g. if your recommended median prop is 13x6 go ahead and try an 11x8P.
This will seem small for your engine.
The caveat will be that the engine will be prone to overheating with the smaller prop.
You'll also need to make sure that the engine is tuned rich particularly in the high end, to prevent overheating.
The plane will tend to overheat more on the ground due to lack of moving air.
Get a laser temperature guage and keep the head temp UNDER 380 degrees, measured at the glow plug base.
Pusher prop planes really need to have their C.G. adjusted and set with the tank FULL.
If not the plane will be far too tail heavy and the stated problems will appear.
Setting the C.G. with the tank empty gives erroneous and potentially dangerous results.
If you set the C.G. with the tank full, the indicated C.G. is fine.
Also: You are not getting a lot of speed out of the plane because your engine is too loaded down by the prop.
I fly a GMS .76 with mine ( both on this plane and my Bobcat 50 ).
The plane flies much like any other tractor plane of similiar size when I use a recommended prop, as you have appeared to have done.
I swapped my prop out for an 11x8 Graupner pusher prop, which is considerably undersized for the engine I used, but provides more pitch.
This reduces the overall thrust in exchange for speed.
My plane is fairly fast this way, turns MUCH higher RPM's, and has plenty of verticle thrust due to the larger engine used.
Your engine is still maintaining low to standard RPM's, so it will not get the plane any faster than what you are seeing now.
For more speed adjust the prop instead. It - MUST - unload in the air and you need a higher pitch.
e.g. if your recommended median prop is 13x6 go ahead and try an 11x8P.
This will seem small for your engine.
The caveat will be that the engine will be prone to overheating with the smaller prop.
You'll also need to make sure that the engine is tuned rich particularly in the high end, to prevent overheating.
The plane will tend to overheat more on the ground due to lack of moving air.
Get a laser temperature guage and keep the head temp UNDER 380 degrees, measured at the glow plug base.
03-08-2010, 01:16 PM
#3
RE: FlyCat 90 video
Hi Op,
the 13x6 prop started out as a 13x6 but then what you see in the video is a 13x6 cut down to an 11x.5 x 6 so Im thinking it is what it is. I agree totally, it needs a higher pitch . I looked around for some different ( higher)pitches but just couldnt find them out there... got any links you could provide for any of these?
Im going to call you out on the cg indicated in the plans
if one was to place the cg at 12 inches and do that with a full tank of fuel where the instructions have you place the fuel tank, which is right next to the firewall,... well I want to be around to watch what happens, but behind the fence of course! LOL
The engine is still tuned rich and I would think if its turning 11,900 on the ground, the engine will unload in the air and most likely get mid 12's in the air. And yes, I realize that the plane needs to get in the air pretty quick, otherwise it gets hot in no time due to no air going over the engine.
Once things warm up here in the summertime, it could be interesting to see how long it takes the engine to get hot
Thanks,
John
the 13x6 prop started out as a 13x6 but then what you see in the video is a 13x6 cut down to an 11x.5 x 6 so Im thinking it is what it is. I agree totally, it needs a higher pitch . I looked around for some different ( higher)pitches but just couldnt find them out there... got any links you could provide for any of these?
Im going to call you out on the cg indicated in the plans
if one was to place the cg at 12 inches and do that with a full tank of fuel where the instructions have you place the fuel tank, which is right next to the firewall,... well I want to be around to watch what happens, but behind the fence of course! LOLThe engine is still tuned rich and I would think if its turning 11,900 on the ground, the engine will unload in the air and most likely get mid 12's in the air. And yes, I realize that the plane needs to get in the air pretty quick, otherwise it gets hot in no time due to no air going over the engine.
Once things warm up here in the summertime, it could be interesting to see how long it takes the engine to get hot
Thanks,
John
03-08-2010, 02:27 PM
#4
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RE: FlyCat 90 video
ORIGINAL: JohnMcGowan
if one was to place the cg at 12 inches and do that with a full tank of fuel where the instructions have you place the fuel tank, which is right next to the firewall,... well I want to be around to watch what happens, but behind the fence of course! LOL
if one was to place the cg at 12 inches and do that with a full tank of fuel where the instructions have you place the fuel tank, which is right next to the firewall,... well I want to be around to watch what happens, but behind the fence of course! LOL
WIth the tank as far back as possible and full, the extra weight of the fuel acts to provide a greater lever moment around the C.G. ( fulcrum).
If the C.G. is set to the manual's reconnemdation, it is effectively similiar to what you did, by moving the C.G. forwards.
In other words, if you set the C.G. to the recommended, with the tank full, you end up adding MORE nose weight to offset the fuel which is further back... exactly as you did...
As far as the props, try searching for Graupner 11x8P props. That's what I'm using with mine.
Hobby-Lobby has them as do other vendors.
04-10-2011, 05:13 PM
#5
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RE: FlyCat 90 video
Super tigre 90 has a two piece crankcase, rotate the front crankcase 90deg you now can run engine in reverse and use all the standard props without being limited to pusher types.
