Gyrobee performance at high altitude

[Gerhard]

I want to build a Gyrobee but cannot start before one final question is answered. Can the Gyrobee with a Rotax 503 fly from a runway at 5000 ft altitude on a hot day? Could anyone with first hand experience of a similar situation please share his impressions with me? I live in South Africa where the summer day temperatures average 86 degree.

[gyropilot]

Gerhard,

I've flown my Bee from a starting altitude of 4300' MSL on a 95 degree day. Going from memory, climb performance after takeoff was about a 300 fpm climb rate, which gradually diminished to about a 100 fpm climb rate at 7800' MSL.

This was using a dual carb 503 (jetted for the takeoff altitude / temp), a 3-bladed 60" Ivoprop, 23' Dragon Wing blades, and a takeoff weight of about 525 pounds.

If I were to permanently operate under those conditions, I would recommend at least 24' Dragon Wing blades, or maybe even 25'. With the 23' blades I was using, blade speed was something 360+ rpm... a bit on the high side, but understandable for the density altitude. Normal blade rpm nearer sea level is around 320 rpm.

Best regards,

John L.

[Gerhard]

Great news! This means that I can build a standard bee. Was thinking of using the 582 Rotax previously. Thank's for the advice on the rotor.

[Ralph]

Remember the virtues of keeping the machine light. Even if you are not constrained by our Part 103 weight limits, avoid adding anything you don't really need.

Ralph

[gyropilot]

Remember the virtues of keeping the machine light. Even if you are not constrained by our Part 103 weight limits, avoid adding anything you don't really need.Amen Ralph.

(Coming from a guy with a 308 pound GyroBee.) :)

John L.