[ULF-1] Fwd: Re: ULF-1....+ engine

From: Member 72
Date: 2011-11-08 17:48 UTC-05:00
Message: #0288

All,

Thanks for all the very interesting replies to my inquiry on motorizing a Ulf-1. I forward my reply to Member 67 to share with you all a possible power approach. A power pod over the wing is not viable because of the too high thrust line. R/C hobby brushless motors and lithium polymer battery packs, I feel, are a viable approach.

Best regards to all,
Member 72

Richard,

Many thanks for your reply. Yes, my first name comes from an early governor of Maryland circa mid 1800's whose name was Member 67 Hicks. It became a family name with my grandfather and father sharing the same.

A tractor engine in the nose makes a lot of sense, especially if fitted with a folding or full feathering prop. The last 2 motorgliders I have owned (Vivat and Super Ximango) had this set up and it works quite well.

I was thinking of an easily removable sling arrangement under the inboard root of each wing with a push-pull pod of 2 electric motors each, and each with folding props. One motor would be on the L.E. and the other on the T.E. The motors would be controlled wirelessly from within the cockpit. This arrangement would simplify the installation/wiring, etc.

I see that the airframe is quite complicated. I am working with an engineer friend to see if we can simplify it, e.g., using blue foam ribs with spruce cap strips and thin birch ply doublers only where needed. We hope to modernize it somewhat to decrease building time.

How far along are you with the build?

Member 67

---- Member 67 <[email]> wrote:
>

Dear Member 67,

First of all let me explain......my last (familly) name is Member 67, I was suprised to see that it is also your first mame!

I'm building a ULF-1 with a view to fitting an engine to it. Yes there was a French gentleman who fitted a 2CV car engine on a pylon, the problem was that due to the height of the pylon it caused too great a turning moment,the tail rose and the aircraft apparently rotated about the front skid and the pylon broke.

For my part I'm fitting the engine at the front very conventionally and using a ZDZ420 flat 4 two stoke which weighs 9.6 kg. and will produce 38 BHP at ~7000 RPM.....more than needed to fly (~10HP), but plenty in reserve for take off and the engine will have an easy time when flying.

I'm quite light myself and so I will need little adjustment for balance. I do like the idea of 2 engines one in each wing, however this would involve much redesign and re-stressing of the structure. Also it would complicate assembly / dis-assembly for flying.

I would add that the ULF-1 is not a quick aircraft to build and it is is quite a complicated structure.

Hope this is useful to you.

Best regards

Richard

(Dr. Member 67)