Jump to content

Alaskan Air National Guard Version


Recommended Posts

  • 2 weeks later...

Today I reached the balancing stage. It needed an extra 50 grams of lead at the front of the battery box. Which makes the all-up flying weight 1.70kg or 3lb 12oz.

img_20201101_110232638.jpg

I've finished all the markings now. I tried the Al Gorham recommended method of doing almost everything with paint masks and an airbrush. After several mishaps with over-thinned paint creeping under the masks, which had o be tidied up with a scalpel and and a small paint brush, this is the result.

img_20201101_110919267.jpg

img_20201101_110854988.jpg

img_20201101_110905552.jpg

Now I need to think about panel lines.

  • Like 1
Link to comment
Share on other sites

Steve glad the masks worked for you eventually. Not sure I'd have the patience to cut them by hand myself though! Well done.

For future reference to avoid paint creep, always spray a light coat of the base colour you are laying the mask over around the mask edges. Let it dry and it seals the mask edges and any creep will be the same colour as the base anyway and thus invisible...

I also don't overthin the paint I'm applying through the mask. If it is a solvent based acrylic such as Tamiya that has very dense pigment then I try not to thin at all!

Good job though!

Edited By Alan Gorham_ on 01/11/2020 19:28:57

Link to comment
Share on other sites

Thanks guys.

Al: Ah yes, that's a good tip about the paint masks. Why didn't I think of that?

Steve: I'm a habitual user of cheap servos! I have a pair of Turnigy 9MGs in the wing, spaced as wide as the fuselage will allow to try to keep the pushrods as perpendicular to the torque rods as possible. I will take a photo tomorrow.

I also have a single Turnigy 9MG for the all moving tailplane currently, but I'm wondering whether it's really man enough for the job. I may upgrade that to a Hitec HS85MG.

Link to comment
Share on other sites

  • 3 weeks later...

Hi Steve .Was thinking about your aileron servo installation and wondering if it will create some mechanical differential due to the position of the servo horn and if so whether it is the right way round ? My physics are not up to scratch .I know that if the aileron horn is angled towards the servo it produces this effect because it happened on my first JP..Does anyone have an opinion on the subject ?

Link to comment
Share on other sites

Hi Pete. the picture above is a bit misleading - probably because of the wide angle lenses in phones. I have tried to keep the servo arms as close as possible to 90 degrees to the push-rods, so that the defections are equal in both directions. But I do have the uprights on the torque rods tilted back a little away from the servo to try to get some of the differential effect you were talking about - more up than down. But to be honest, so long as you've got enough movement in both directions, it's all programmable on the Tx anyway, so I'm not sure I needed to bother.

Link to comment
Share on other sites

  • 8 months later...

Just an update to record the first flight, which happened at the Great Orme PSSA event last weekend. Thanks to Phil Cooke for the photo.

All went well and the model got down safely and remains in one piece ready for the official mass build event on Sept 18/19. 

 

Whilst the model flew well enough to do a few passes along the slope, I found the elevator response to be really sluggish, and I was worried that I just didn't have enough up elevator movement - to the extent that I didn't feel comfortable to really explore it's capabilities. Having discussed this with Martin after the flight, and gone back to the balancing jig, it looks like this could be all due to a poor CG position.

 

I had missed Martin's note on the 'Gotcha' thread about the CG position [which says that the position shown on the plan (165mm from F4) is a bit conservative (nose heavy) and that most of the models already flying are set at about 172mm]. I had worked from the plan (mine seems to show 164mm!) but then I had a been a bit conservative just in case this setting was the 'rearward limit' setting as I often find on plans. So I had allowed it to come forward another 3mm to 161mm. 

 

So, I have now removed a bit of lead from the front of the battery box and moved the CG back to 170mm. This has the added benefit of reducing the all-up flying weight to 3lb 10oz. I'm now looking forward to flying the model again in a few weeks time at the official Sabre mass build event.

 

51373778916_b324c76967_k.jpg

  • Like 4
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...