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First build from Flite Test

#1
Hi,

I just built my first Flite Test aircraft, Josh's tribute to the DH88 Comet, the Cruiser.

http://www.shuttleworth.org/collection/dh88comet/
https://www.baesystems.com/en/heritage/de-havilland-dh88-comet

Still to fly, as I have ground clearance issues with the props. I can't use the foam wheels, as the area where I fly would rip them up after a landing or two. The wheels I have (off the Durafly Vampire) leave no ground clearance. I also need to make a canopy.

So I have a couple of thoughts

1 - Could I put retracts in the power pods (as there is no battery there) to clean up the plane in flight. PP's are easy to build, and I don't think the engineering is too hard. If I do make it happen I'll post pictures. I'll also clean up the back of the nacells to make them more streamlined

2 - Could The team take the DH88 Comet ideas and turn it into a DH98 Mosquito? It would be a Foamboard Wonder not a Wooden Wonder! The compound curves now used on things like the F4U would make a DH98 possible I think. Take it as a challenge !

Regards

Gordon
 
#4
The retracts idea is in my head, needs a little more work.

Power Pod Modifications

skin front half of inside bottom plate of power pod with Plywood (thin)
Use a B fold to bring up the sides cutting around ply wood.
Mark and cut recess for retract ensuring fixings are into plywood. Need to look at COG with retract, as COG will move as wheel retracts.
Mark and cut wheel well and slot for landing strut.

I also want to change the back of the nacel / powerpod to be angled in to a point, like the original.

As it's swappable I can make a few variations until I get the locations correct.
 
#6
The thing is unflyable, Have tried 3 flights all disasters.

On take off it just pulls ups with power on. no lateral control no vertical control.
It just about glides.

Have changed the linkages from the build video as that gave 200% more travel on tail surfaces.

Elevator was bent after first flight as the link left to right was not strong enough.

COG is correct as per the build video. Have tried it forward and rear no real difference.

Props supplied with the recommended power kit are too big. I'm on 8x4 and it still seems to be over powered.

If anyone has any ideas as to why I'll give it one more go if not it's into the bin. What a waste of money.
 
#8
I’m having the same issue as Gordon. I just tried my second flight with the FT Cruiser. I have it set up for 190 watts with a 9x7.5 prop. Using a pair of motor I dug out of the motor box, not sure what the KVF rating is exactly, just hooked up a few props until I hit on something that wouldn’t over amp the motors.

Anyhow, there’s more than enough power. When I have the throttle on the plane climbs until it stalls, without constant forward stick it climbs. I already have the COG 1” forward of recommendation. I’m thinking it has to be a thrust line issue, once the power is off it noses over.
 

Hai-Lee

Old and Bold RC PILOT
#10
The motor thrust lines could be the problem or at least part of the problem but I would also recommend that you check the wing and tail incidence angles. It is a common build fault to have the wing too positive in incidence compared with the tail and as the speed builds the wing lifts and the tail doesn't. The tail is shadowed by the wing and you loose control. This is especially important in trying ot gain sufficient ground speed to allow the tail to function as designed.

If the wing flies before the tail the plane will lift off without any real means of control and the result is a rapid nose up climb followed by an uncontrolled crash!

Just my experience!

Have fun!
 
#11
Whatever the issue was, it’s no longer an issue. I don’t have time for the aggravation this plane gave me. Motor thrust lines didn’t change anything. Wing and tail angles were good. It’s just a junk plane. It’s not worth the work. I gutted the electronics out of mine and pitched it in the trash.
 

Merv

Well-known member
#12
It’s just a junk plane. It’s not worth the work. I gutted the electronics out of mine and pitched it in the trash.
Some planes are just easier to fly than others. Give one of the trainers a try, something like the Tiny Trainer, Storch or the Simple Cub.
 
#13
Some planes are just easier to fly than others. Give one of the trainers a try, something like the Tiny Trainer, Storch or the Simple Cub.
I’ll just stay away from the Cruiser. I have plenty of other planes that I have been flying for the last 15 years that fly well. Not going to waste time and frustration on a bad design.
 

Timmy

Well-known member
#14
Some planes are just easier to fly than others. Give one of the trainers a try, something like the Tiny Trainer, Storch or the Simple Cub.
I agree, the Tiny Trainer is hard to mess up with (not that you messed up) and you can ajust the design to be your own pretty easily. I modded it so the prop is on the back in a bixler type configuration because I was breaking too many props.