"Dead-Stick" Challenge!

[quorneng]

Monte.C
Yes maximum power from the motor is good but that power has to be converted into thrust at the speed the plane climbs at. You have to find the best (and workable) solution of several, possibly conflicting, parameters and that is just for the 10 second 'going up' bit!
I suspect a good overall solution might involve variable geometry as well.
This challenge is rather more involved that it might appear!

 

[Monte.C]

Monte.C
Yes maximum power from the motor is good but that power has to be converted into thrust at the speed the plane climbs at. You have to find the best (and workable) solution of several, possibly conflicting, parameters and that is just for the 10 second 'going up' bit!
I suspect a good overall solution might involve variable geometry as well.
This challenge is rather more involved that it might appear!

Yes of course. However, most people won't be building a variable geometry wing, or using a multi-stage rocket motor, or a droppable power pod, or consulting with an aeronautical engineer. Most will choose a plane they feel comfortable with building, or even one they already have, and use a motor they feel is ok for that plane. There are options for cell count for that motor, and the most aggressive move is to use the max cell count with the minimum kv rating to save on weight.
"...but that power has to be converted into thrust at the speed the plane climbs at." Choose a propeller.

Edit: largest cell count, minimum mAh.

 

[mastermalpass]

I'm guessing we're extending the deadline as we've only had two videos so far?

Think I might have another shot. I did not balance the weight very well on my first take, which is why the plane dived as soon as I finished the climb. Might try with the 500mAh 2S this time. I went with the much heavier 800mAh 3S on the first go, assuming greater inertia was key to keeping this very draggy design from stalling. But maybe it already has enough inertia to push its swept wing through the air without stalling. It was certainly gliding faster than I usually prefer to power-fly it when carrying the heavier load lol.

 

[BlockerAviation]

I'm guessing we're extending the deadline as we've only had two videos so far?

Think I might have another shot. I did not balance the weight very well on my first take, which is why the plane dived as soon as I finished the climb. Might try with the 500mAh 2S this time. I went with the much heavier 800mAh 3S on the first go, assuming greater inertia was key to keeping this very draggy design from stalling. But maybe it already has enough inertia to push its swept wing through the air without stalling. It was certainly gliding faster than I usually prefer to power-fly it when carrying the heavier load lol.

yeah the deadline has been extended to Jan 15. I think most people saw this challenge half way through the allowed time so they couldn't get an airplane and a flight done.

 

[Phin G]

The UK is now in a nationwide full 'lock down' so RC flying is rather questionable however just in case it should prove necessary I have prepared my plane to use a half size (& weight) battery that should both improve its climb rate and reduce its sink rate.

Yeh i am doing my first balsa scratch build. It took me 1hour to cut out one wing and i even forgot the wing spar. Oops.

 

[Phin G]

Just finished my first eletronic build/ plane with eletronics and it looks terrible. No turtledeck or back side plates. I shall test flight tomorrow and send vid

 

[Matthewdupreez]

Just finished my first eletronic build/ plane with eletronics and it looks terrible. No turtledeck or back side plates. I shall test flight tomorrow and send vid

what type of plane is it?

 

[quorneng]

I am almost certain the UK lock down will prevent this being actually tried but this is the 'lightweight battery' modification I had intended showing the position of the big battery used in the video flight and the revision.

With a new slightly longer but hollow nose glued in place would allow the 1500 mAh 3s battery to be stuffed right forward to maintain the same CofG.
The 3000 mAh 3s 30C weighs 8.38 oz, the 1500 mAh 3s 40C Nano Tech weighs 3.74 oz a saving of 4.46.
That would represent a reduction of 17% on the 26.15 oz plane all up weight used on the video flight.
Of course it is quite possible the smaller battery would not deliver exactly the same full power, a 45 A discharge for even 10 seconds would not do it much good either, but the not insignificant weight saving weight saving should have an effect both on the rate of climb up and the sink rate on the way down.
Oh! well never mind I doubt I will ever find out!

 

[Phin G]

what type of plane is it?

An fugly Bi plane

 

[Matthewdupreez]

An fugly Bi plane

fugly.... does that mean funny and ugly?

 

[Matthewdupreez]

An fugly Bi plane

can't say it is good looking

 

[mastermalpass]

fugly.... does that mean funny and ugly?

Err... No it's not typically used to mean 'funny' and ugly, but you have got the first two letters right.

 

[Phin G]

can't say it is good looking

Yeh i want to put a turtledeck on it but it is 6g overweight

 

[Matthewdupreez]

Yeh i want to put a turtledeck on it but it is 6g overweight

6 grams for what.. a plane should fly even if it is slightly over the thrust specs of themotor

 

[Phin G]

6 grams for what.. a plane should fly even if it is slightly over the thrust specs of themotor

Good to hear i am probably maidening her tomorrow

 

[Matthewdupreez]

Yeh i want to put a turtledeck on it but it is 6g overweight

put a turtle deck on with tape and then if need be you can easily remove it (sellotape works really well)

 

[Phin G]

put a turtle deck on with tape and then if need be you can easily remove it (sellotape works really well)

Ah i had just been using hot glue and it adds alot of weight so ill try cello tape

 

[Phin G]

Maidened the fugly bee and crashed it and snapped the rear off. Easy fix if i had any balsa wood. 😅🤣

 

[BlockerAviation]

Just a friendly reminder that all entries will be due by Jan 15, 11:59 pm of whatever timezone your in. I will be announcing the winner on the 16th.

 

[Phin G]

Just a friendly reminder that all entries will be due by Jan 15, 11:59 pm of whatever timezone your in. I will be announcing the winner on the 16th.

I sm afraid i had to pull out since there is a £300 fine if you go out flying and i crashed and it snapped the plane. We also live opposite a police station sooo we would get caught