Joyrider Pitch Frame Bearing Location

Hi SimBuilders,
This information may be of use to those embarking on a joyrider-type project. Most important is balance, so the bearing points you choose for the pitch frame must be very carefully done---meaning that all the exact components, yourself included, must be chosen and correctly positioned along the longitudinal axis so you can accurately find the balance point. Sure, you'll have to compensate for different pilots, but that will be small.

I made a big blunder here by first setting up for a 19 CRT monitor, and then changing it to a 19 LCD later! Huge weight difference, not to mention that it is placed pretty far forward as I also use a Fresnel Lens---maybe 9-10Kg, and huge unbalance to compensate for. Drilling new bearing points weakens the frame, specially a thin-walled 1 1/8 metal-tube one, like mine. I now have to think of shifting my pitch frame bearing points to the rear by about 3-4 :uups:

Just a word of caution!!

Regards, Erich..........

Hi Again,
Managed to solve the problem mentioned in the post above---but not in the manner I thought I might have to. I was very fortunate to be able to find a way without having to drill new holes in the frame to bring the pitch frame bearings backwards by about 3. The seat support plate is held by 4 slideable straps enabling the whole seat to be slid forward. A number of clamps, straps, and the position sensing pot, etc., blocked this movement. Removal and relocation of these items gave enough space for a 2 1/2 slide forward, slightly less than I had hoped for, but nevertheless, adequate. Please note that the balance could be achieved by either moving the pitch frame bearings backwards, or moving the seat supports (and therefore the seat) forward, just to avoid any confusion on this point!

Happily, everything worked out, including a worry that the control column movement might be restricted, but this too worked out. My constant and long-suffering companion Stone Temple Pilot helped a lot with the balancing act.

This apparently small shift of the CG enabled me to remove 6 Kg of forward ballast placed about 30 forward of the pitch frame bearings. Now that's a huge amount of unnecessary mass which had to be moved by the pitch motor!!

The attached pics, I hope, say it all!

Hi,
After the CG change, I needed to check the platform response, and what better test than heavy turbulence in a small Cessna!!

Here it is: http://www.youtube.com/watch?v=5rgwXlD6WHk You can also get it direct by going to 'Erich's Flightsim' page

Regards, Erich.