Thursday, August 27, 2020

Crofter first flights


Evening hardly any wind, on the day I maidened the CROFTER 24" simple glider. I found it very hard to trim. Took me a long time to get it to tow on the High Start (30m), and the glide starts stally, then tends towards a spiral dive. 

I think the fin is too big, and have since cut it down. I've also experimented with moving CG forward to 40% (it was about 50% on the plan), but it didn't help very much. I may try to move CG backwards to about 55% and see if that helps. 

However, I now believe that this glider for a newbie would not be as satisfying to build and fly as compared with a simple well-designed model with tissue covered wing. 

So, to check that, my daughter has agreed to build a West Wings Merlin 35" wing span, which is a well regarded kit. We'll compare it with this one for ease of launching and trimming - and overall satisfaction. Not really a fair test though, because it has a bigger span and more complex construction.

But I also have a 24" wing that was built a few years ago by my son for a school competition. It's based on John Barker's famous LULU. Here it is after steaming, banded to a board to get a warp out:

I should be able to to fix this wing temporarily onto the CROFTER fuselage. It weighs 8.43g as compared with the CROFTER'S which is 12.3g - that's 30% lighter! It also has significantly more wing area (90mm chord vs. 75mm on the CROFTER, giving about 20% more area if my maths is right). I'll balance it at about 50% and see how it behaves. It will be an interesting experiment!

Newcomers need something that gives good results relatively easily, in my view.

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