Jump to content

Folland Gnat Build


Steve McLaren
 Share

Recommended Posts

Steve,

Thanks for the info. I hadn't thought of Solartrim, but I did use inkjet printable vinyl on the JP. I found the design and printing relatively easy, but cutting out the letters was a patience-trying exercise, and mine ended up rather ragged. The clear vinyl is also starting to loose its ink, even though I applied a coat of sealer.

The servo info is useful. I used 9g New Power 'cheapies' on the JP, but I do have trouble looping it and was wondering if the servo could be blowing back, hence my question. However, I didn't have any problems in normal flight in the strong winds at the Lleyn last year.

I share Mark's curiosity about your foam cutting, and will be interested in your rig. I'm part way through making one so that I can start on the Jack Edwards Zlin 526 Akrobat, so that I'll have something to fly on Zephyr days. Very little progress at the moment, due to having a very busy family with needs for assistance.

Link to comment
Share on other sites

Thanks Steve - that's very kind of you (I felt a little cheeky asking). I've done a few small "plunge moulded" forms for free flight and control line models in the past, but I reckon that this one has to be a pukka vacuum job. Given that the magazine article / plan that I have is dated 1995 the suggestion of using a "suitable" tucano canopy could mean anything - probably even one from dearly departed Chiltern Models (I wish that I'd secured one of their Piston Provost canopies when I had the chance !)

Link to comment
Share on other sites

  • 1 month later...

Thanks guys - still no first flight yet, but it's definitely getting close now as the weather gets a bit warmer.

John, I'd be very happy to get another canopy vac-formed for you. I've discovered they can be mailed for the smallest lightest 2nd class parcel rate of £2.80, plus the £5 for the local model shop, gives £7.80 total.

As I said above, I can only get to the LMS on Saturday mornings, so it takes a whole week to turn round an order. Maybe I should get some stock - but would anybody else ever want one??

I'll send you a personal message with my contact details.

Link to comment
Share on other sites

  • 4 weeks later...
  • 8 months later...

Hi Andy, So you are starting on it then? I'm sure I just read read one of your posts on another blog saying you were starting on something else in the near future? It's certainly an impressive production rate down at your factory!

On the wings, I went for 34 inch span. There is a picture on page 1 of the blog which sort of shows the change I made. Basically I moved the tip in by the full width of the tip (about 2.5 inches). What I didn't do (and now regret) was change the taper angle of the leading edge to get the same chord length at the tip. So my wings look a little to 'square' to me. So you have the chance to improve their.

I have been meaning to come back to this blog to finish it off properly, but so far just haven't got round to it. So I'll do it now.

It took me a long time to get to some successful flights on this model. But Phil Cooke has kindly given me permission to add these pictures which show that this model does indeed fly very well, when you eventually get the CG position right. Thanks very much Phil!

editimg_3662.jpg

editimg_3667.jpg

My initial problems were all caused because, not being used to highly swept wings, I set the model up using the CG position suggested on the plan, forgetting that I had cut 2.5 inches off each wing tip. So the initial CG was way too far back. This resulted in not one, but two flights where the model tumbled uncontrollably backwards over my head and into the heather!. One of the impacts lead to a slight shortening of the nose, but it did demonstrate what a robust airframe this is!

So then I moved the CG well forward, which resulted in a rather sluggish performance, and I have been gradually working my way backwards. These pictures cam from the last PSSA event of the year at the Great Orme, where I think the CG was getting to a pretty good point.

So if anyone ever uses the same wing size as I did, you may want to know that the current CG position is 155mm from the leading edge (or former F2) and 110mm from the trailing edge (or former F4), where the wing intersects the fuselage sides. i.e, 25mm further forward than shown on the plan. I might take it a bit further back yet, but this should give you a good safe starting point. And if you decide to go for a different wing shape, it might help you to estimate a good starting CG position.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...