The Aero-Bicycle - Part II (Red Bull challenge)

by Eggs Benedict | August 8, 2018 | (3) Posted in Challenges

This is the second part to my attempts at making a model bicycle (and intrepid rider) fly. If you haven't already read part I, you can find it here.

After some inspiration from watching Those Magnificent Men in their Flying Machines (I highly recommend it for the aspiring aviation pioneer), I was ready to have another go. I feel Harold Spiffington, that indomitable moustache-wielding cavalier of the skies, has a good chance of soaring gracefully through the air. If not gracefully, then at least controllably.

I have glued the motor mount on more firmly, and also attached the rubber band holding the battery in place in a more robust fashion. I also secured Spiffington in an upright position by gluing barbecue skewers inside his coat and attaching them to the bicycle frame.

The skewers make him wobble about less and having him sit upright of course looks more stylish than having him bending over and taped down. However, this is probably less aerodynamic and I feel like I might have to make the tail bigger for better control. I think I'll try it this way first though. If it flies for longer than thirty seconds, I think I will be happy.

To fix the balance of the plane, which I think is probably too tail-heavy, I decided to stick some weight to the front. I could possibly just use a bigger battery as it is right at the front, but this is the one I have, and a bigger battery might not fit anyway. I decided to invest in a different method...  I am going to use coins. This will allow me to change the amount of weight as I see fit, and I am going to bring some to the field so I can make changes if need be. I am going to use (Canadian) 5 cent coins because they are fairly big, and not too expensive.

I have stuck these to the front with tape.

I am almost ready to give it another go. There are just two things I need to sort out before I can send Spiffington hurtling into the blue. First, I need to secure the propeller on. The screw cap is still Missing-In-Action after last attempt (see the video in Part I). Hopefully, I will be able to find it this morning. Otherwise, I will have to go to the hobby shop and get a new one. The second issue I have to deal with before take-off is that the elastic bands holding down the battery have come slightly unstuck on one side again. Once I have fixed these two things (and charged the battery) I will be ready to go.

I couldn't find the cap so I went to the hobby store and bought some lock-nuts, which actually work better because they have a coating on the inside to make them stay. This time, I tightened the nut on with a wrench instead of just by hand like last time (probably why it flew off before).

Then, once the battery was charged, it was time for another go at flying.

Well, what happened?

First, I realized that the ailerons were loose, because the paper layer on them was detaching (my rookie mistake coming back to bite me again). This was a fairly easy fix; all I had to do was tape the paper back down (hooray for my field kit, now with scissors). Next, I noticed that the motor was making a funny sound when spun up to higher throttle. I think this sound actually came from the wheel vibrating against the frame.

When I actually launched it, it still kept trying to flip on its back. One flight had a bit more success than the others, but still had the same problem. I decided to double the number of coins at the front. Still no luck. I am surprised at how well the plane has survived, considering how many times I've crashed it. 

My scissors came in handy once again when I used them to cut the wings down at the leading edge corners, to move the centre of lift back and so make the plane less tail-heavy. Still no banana. I tried removing all the coins just as an experiment to see if the plane was actually too nose-heavy. Nope.


Then my ailerons started acting funny. It seemed that they developed minds of their own. They were moving without me touching the controls! I tried re-binding the plane to the transmitter. All the other electronics worked, but the ailerons just suddenly wouldn't move. I decided to scrub the attempt and take a break before fixing the problem at home.

So that's where I am now. It's still my first time making a plane by myself, so there are lots of places I could be going wrong.  I am going to try re-binding the plane to see if that fixes the ailerons. I think I will make the nose longer so I can put the motor and battery ahead of the wing. 

I tried doing the math to find out where the centre of gravity should be, but due to the fact that I did not make very detailed plans at the start, it is a bit difficult to get the measurements. I think I will still try to make these calculations, but first I will make the wings more robust and give them an actual airfoil rather than having them just be flat pieces of foamboard like before. This time, I am planning properly before I build (although it is more of a sketch to do math with than a blueprint):

As I planned above, I have made a proper airfoil for the wings, which also has the effect of making them less floppy, as well as hiding the servo wires and making for a more professional look.

I am hoping to fly again soon, so check this page for updates. 

To entertain you while you wait:

Spiffington will fly again!


Damorc on August 10, 2018
Pic or Spiffington inverted is brilliant!
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buckineer69 on August 14, 2018
If Memory serves me the direction of the motor {SHOULD} spin the prop nut on too the propeller check your threads and change the polarization and prop accordingly

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The Aero-Bicycle - Part II (Red Bull challenge)