The Cost Of Building: Recording The Financial Cost of Building a DB Sport & Scale Skyrider. A Surprise for Miss Blue Eyes.

[Ace]

 

I use this from 4 max which I find very useful and should help with power, battery size and duration  trade offs ?

 

Working out power train for electric.pdf

Edited November 26, 2022 by Ace

[David Davis 2]

Well I flew it yesterday. It flew well enough requiring some up elevator and left aileron trim. It was not a ball of fire and the ailerons were a bit soft but there are things which I can do which will improve those two aspects of its flight performance. However, there was one aspect of the flight which really took me by surprise. At a good height I throttled back to test the stall characteristics and it suddenly dropped its left wing and fell twenty feet. This is despite having a cg forward of the position marked on the plan. The same thing happened on the second flight when I was landing the model. I broke the prop but otherwise the model was undamaged.

 

In thirty-four years of flying radio controlled models I have never known a model stall so viciously. The club chairman suggested putting more weight in the nose, but that's his answer to most bad flying characteristics!  Wouldn't extra weight simply increase the stall speed?  On the other hand he has competed in the French Nats. I haven't! Perhaps I'd better get used to landing it at high speed.

 

The target weight for an i/c Sky Rider is 5lbs though weights of up to 6lbs are acceptable. Mine weighs 4lbs 9ozs with a 3000mAh 3s LiPo. I could replace the 3000 mAh LiPo with a 4400 mAh Lipo which would bring the balance point forward. I had marked the cg position on the fuselage with two small white Solartrim triangles. I intend to check my measurements.

 

What do you think?

[David Davis 2]

I flew it yesterday with the 4400 mAh LiPo installed. The extra weight brought the cg forward and appears to have delayed the stall which is still pretty vicious but maybe I'm just getting used to the model. I managed loops, rolls and Immelmans and a successful landing.

 

I was describing its flying characteristics to a friend who is not an aeromodeller when she suggested adding some weight to the starboard wing because it always dropped its port wing when it stalled. I tried balancing the wing and found that the port wing was indeed heavier. I taped a 5 centime coin to the starboard wing tip as a temporary measure. The port wing still dropped at the stall but it may have made it less vicious.

 

Final thoughts on the Sky Rider? It's reasonable value for money, easy to build and it flies well, stall characteristics not withstanding. It costs £30 less than an ARTF WOT 4 and fully £100 less than a Speed Air. Though mine flies well enough and can do basic aerobatics I feel that it would benefit from extra power, I'm hoping that a change of propeller will achieve this, or am I expecting too much from a model billed as an aerobatic trainer?

 

The pink shows up well in flight.

 

 

Edited November 28, 2022 by David Davis 2

[David Davis 2]

P.S. The wing seat on my model did not match exactly the profile of the wing ribs. It was too deep in the middle. This could have been caused by an error in construction on my part but equally perhaps, the profiles which are part of the plan pack did not match the wing ribs supplied. I have "engineered a solution" by using adhesive backed foam to seal the gap. Were I to build another, I would make sure that the wing ribs and wing seat matched.

[J D 8]

  Have you checked the wing for warp ? Was it built with any washout?  How much left aileron trim did you need to put in?

A snag with strip ailerons is that any more than a tad of difference between left and right can result in a change in wing profile altering the aerodynamic performance of one or both wings.

    One could level up the ailerons and then as the model has some dihedral [I think] see if you can straighten the flight with some rudder trim to solve the stall issue. Just an idea. Cheers, John.

[Nigel R]

Skyrider should have a stall that's softer than a melted ice cream. Would agree about checking for warps, got to be the prime suspect.

[kc]

Looking at the photo posted on Oct 22 there would appear to be a significant warp although it could be just the angle that caused or exagerated it.

[David Davis]

If the wing is warped it's so rigid that it will be impossible to remove it without recovering it.

[kc]

It is usually easy to spot a serious warp by viewing dead centre from behind and looking to see if trailing edge compared to LE both sides look equal.    Needs a straight eye of course and not everyone has that advantage.  

If you cannot see it it may be worth asking someone else to be sure before hacking the wing around!

If my view of the Oct22  photo is correct ( may be just an optical illusion in the photo of course) then it's likely it happened when the final wing LE sheet was applied to that side.   Remedy might be removing that sheet and re doing whilst pinned down correctly- might only need covering removed on that piece.

[David Davis]

I'm afraid I've got too much to do just at the moment kc! It flies reasonably well provided that you keep the speed up on landing approach. It will only be flown on high days and holidays, mind you, I am tempted to take it flying this afternoon and try it with a 4s LiPo if only it wasn't so cold.

[kc]

A job for a cold winter day perhaps.......

A plane that doesn't fly well is a pain forever while a nice flying one is a delight.  Worth the effort to get it right.

 

Dont do anything drastic until you are sure it's warped!      My view might be 'warped' but it's also based on looking again at your photos from Oct15 which to me show a warp, but it's very difficult to be sure when the camera is off centre.  If you re photographed the wing from dead centre behind other forum members might give their opinion about warped or not.

[J D 8]

 Or have a go at my suggestion in post above next time out.

[David Davis 2]

JD8, what do you mean by "level up the ailerons?"

[J D 8]

I presume from your first flight report that you had to dial in some aileron trim to get it to fly straight. If so then take out the trim you put in, level ailerons by eye then put in some rudder trim in the direction you need to fly straight. Model would need a bit of dihedral for this to work. Bit of a get around for a warp on a high wing.

[David Davis 2]

Thanks JD8. I'll see if I can fit that in this afternoon.