What Did You Fly Today

Crawford Bros. Aeroplanes

Legendary member
I think just the opposite, disregard the canards and do the cg calculations again and see what you end up with.
Disregarding the canards the cg should be just ahead of the trailing edge root. I can't calculate where the cg actually is without building the model, only where it needs to be. If it ends up being tail heavy then that's actually better, it'll be far easier to put weight in the nose than the tail.
I would think the weight would be pretty centralized. This will be interesting to test lol!
We'll find out one way or another.
 

Wildthing

Legendary member
Disregarding the canards the cg should be just ahead of the trailing edge root. I can't calculate where the cg actually is without building the model, only where it needs to be. If it ends up being tail heavy then that's actually better, it'll be far easier to put weight in the nose than the tail.

We'll find out one way or another.
If you have the measurements try these links, 1st one is to use with the canards. :)

https://rcplanes.online/cg_canard.htm

https://rcplanes.online/cg_wing.htm
 

Timmy

Legendary member
Well I guess after 4 months of hanging from my ceiling enjoying the indoors, the day of reckoning for this has finally come...

View attachment 173192

For the maiden I had one of my club instructors with a good 45 years of RC experience take it up for me, but nonetheless it wasn't without incident, though thankfully the majority of problems occurred on the ground. Firstly the screws holding the wing struts to the bottom of the fuselage immediately stripped out. I honestly can't say I didn't expect this to happen since the fuselage bottom is constructed from just 3/32 balsa sheet and it's pretty soft sheet at that. Oh well, it's what the plans told me to do... I guess to remedy it I'll put in some 1/8 lite ply or something for the screws to go into, so they'll be less inclined to leave the airplane. Anyway, the flight went on after we just took the wing struts off. They do nothing structurally so it's not like their absence was a real problem. I might have skimped slightly on the toe-in angle on the gear - you generally want about 2 degrees toe-in total to give good ground handling, but I did that stage of construction in like December of last year so it's not like I remember what I did exactly. For that reason trying to take off from the geomat turned into groundloop hell and we had to use the grass.

From there though it actually went relatively well. The primary issues encountered in the air were a crappy CG and sticky ailerons. It was a little tail heavy and needed loads of down trim, and I'm thinking the 1 3/4 oz of nose weight I added wasn't quite sufficient. Might need to add another ounce. Not like total weight is a problem - contrary to what I expected, in the power department it seems fine. I guess that ASP 52 is enough after all as I saw for most of the flight it was putting around at barely half throttle. I filled the 10 oz tank to the brim and after probably 10 minutes of flight I drained it and it'd only drank probably 25% of it.

The ailerons though, that's a much more severe issue. It had issues where the servo refused to properly center, making trimming it to be level incredibly hard - I'm like 99% sure the aileron bellcrank system is causing it. Airplanes have no real need for them now that servos aren't dummy expensive like they were in the old days. I'm really not sure why I decided to stick with the plans and build it with that system instead of swapping it with a dual servo system which in hindsight would have been much better. Oh well, more work to do...

Here's a shot of the car this morning. I'm really not sure how I got all these in here. I actually got to fly all of them too! Well, except for one. The Littlest Stick's engine refused to start...

View attachment 173193
Thats a lotta yellow.
 

Timmy

Legendary member
Finally flew my Bronco for the first time today. The motor got pretty hot after just on min of flying at a bit under 3/4 throttle. I think I'm gonna switch to a 9" prop rather than my current 10". Any other ideas as to why it could be over heating?
 

Wildthing

Legendary member
Finally flew my Bronco for the first time today. The motor got pretty hot after just on min of flying at a bit under 3/4 throttle. I think I'm gonna switch to a 9" prop rather than my current 10". Any other ideas as to why it could be over heating?
Working to hard so yes prop it down.
 

Timmy

Legendary member
Working to hard so yes prop it down.
Another theory I have is friction between the prop shaft and the motor shaft causing heat which can be fixed by changing the direction of the motor. If that doesn't work then I'll prop down.
 

Crawford Bros. Aeroplanes

Legendary member
If you have the measurements try these links, 1st one is to use with the canards. :)

https://rcplanes.online/cg_canard.htm

https://rcplanes.online/cg_wing.htm
Those are the formulas I'm using actually, I know where the cg needs to be for stable flight I just don't know if I'll need weight in the nose or the tail to get it there. I'm starting to agree with you that it'll be tail heavy empty, but that's pretty easy to fix by putting the batteries up in the nose and if I really need to, moving the canards back a bit or shortening them.

Here's the article I was using, it has the same formulas but also some tricks for doing them easier:

http://www.airplanesandrockets.com/...ters-april-1968-american-aircraft-modeler.htm

This might be a good reference too, I've found a few planes on Outerzone with a very similar planform to mine, but they're all mostly rocket gliders!

https://outerzone.co.uk/plan_details.asp?ID=7033
 

Vimana89

Legendary member
Here's the new tailless build I've been working on. I like it, it's fresh and different from a lot of lower aspect and/or tailed planes I've been doing lately. It's a bit of a challenge to fly and hard to land right, but I enjoy it and it's helping my skills grow. It's not a good plane for a beginner, but for what it is, it flies surprisingly good and the stall behavior isn't quite as bad as planes this planky usually are.
So to the people who fly a lot of planky planes like this, what are your secrets to success in building and flying?