Composite Glacial F3A from Lithuania

[Philip Lewis 3]

I hope so too Peter, maybe Friday maybe next week, I did take it out for its first drive today to carry out a proper range check, all good (obviously).

[Philip Lewis 3]

Maidened today, no drama, no issues, actually needed about 1mm of down elevator to fly straight and level so I'll set to work on dialing that out on the horizontal stbiliser incidence adjusters.

 

[Peter Jenkins]

Sounds like another successful F3A setup from the word go with the exception of the need to tweak the tail plane to lose the elevator trim.  That seems to be a disappearing feature in the BJ Craft range.  You just have to put up with a deflected elevator.  At least the aileron trim can be taken out with the incidence adjusters.

[Philip Lewis 3]

These are the other way round, being a bi-plane it's not possible to adjust the wing incidence at all, that is fixed so the incidence adjustment is in the horizontal stabiliser instead. Good to have got the first flight nerves out of the way though, C of G as specified seems to be perfect, quite unusual, I normally have to move it back.

[Peter Jenkins]

That's Lassi for you.  Exact!

[John C]

On 02/09/2024 at 15:33, Philip Lewis 3 said:

A close up of the servo linkage, that's a ball raced linkage on the horn end and the two alloy couplers are left and right hand threaded to create a turnbuckle, rod is 3mm carbon and the servo end is a ball link.

 

These look excellent.  Where did you buy the alloy couplers and the ball raced linkage?  Also, why no ball raced linkage on the servo arm?

[Philip Lewis 3]

Hi John,

 

You can get the alloy couplers from quite a few places such as Nexus but I got mine from MP Jets because you can buy both left hand and right hand threaded from them to create a turnbuckle, simply glue the carbon in using medium CA, carbon really glues well to both metal and wood with CA.

 

Ball raced links I got from Ali Express. I find Ali Express very good for small obscure parts such as the type of canopy latch where the pin can't slip back in the control pin, I also get anodised coloured washers from there.

 

You can't really use a ball raced link on the servo arm as that end is moving in two planes meaning the end would need to turn as well as bend up and down, it's not much but it's definitely there. 

[John C]

Hi Phil

 

I am sorry about my slow reply (I forgot to follow your thread and then got distracted!).

Thank you very much for your very detailed and helpful reply and for going to the trouble of providing all those links to useful products.  All very useful information.

 

I really like the idea of a turnbuckle so you don't have to disconnect a ball link and you have very fine control of the pushrod length.  I also see that you maintain an equal length of thread in both ball links.  And with the carbon fibre tube you can make it to measure and glue it at exactly the right length too.  A lot to like.

 

With your turnbuckles I am wondering what you plan to use to grip them if adjustment is needed.  I see MP Jet sell knurled aluminium setting rings, presumably to glue on the CF tube which I suppose you could grip with pliers without causing marks on the aluminium ends? 

 

Thanks, I wasn't sure what freedom of movement the ball raced links have so now I understand.

 

I have found your whole thread interesting and helpful.  I plan to copy the way you made your lipo tray support with square CF tubes.

 

Thanks for documenting your build in such detail.

[Philip Lewis 3]

Hi John,

 

The way that I put them together is to screw the aluminium ends into the ball links then cut the carbon rod or tube to as accurate length as possible (it's OK to be slightly short but can't be too long) and then glue the carbon into one end of the couplings. I the connect up the servo to the receiver and power up and that will hold the servo at neutral, then clamp the aileron into the centre and glue the other end and let it set connected, that way it can't really be any more than slightly out which is pretty much as you said.

 

They aren't that hard to turn in the nylon so all I do to adjust is to put some heashrink in a U shape over the aluminium and then the pliers grip the heathshrink which won't slip on the alloy, that way you won't mark the alloy with the jaws of the pliers, also helps to also hold the ball link centrally or that will try and turn on the ball.  

 

Using the square rather than round tubes means that the tray won't slip on the tube during snap rolls but still has a very easy way to get out and put back should you need to, (just cut the tie wraps and then use new ones), but is just so simple and easy rather than going to the trouble of using screws bolts etc to make it removable.

 

Phil  

[John C]

Hi Phil

 

That all makes sense and it is very good to hear that they are not hard to turn. 

Thanks for the tip about protecting the aluminium with a piece of heatshrink.

 

I hope that the model is flying well after your meticulous build and living up to your expectations.

 

Thanks again for taking the time to answer all my questions, you have been very helpful.

 

John 

 

 

[Philip Lewis 3]

Yes John, it has now been flown about a dozen times, it's now been trimed to fly straight and level using the incidence adjusters in the tail to do so rather than trimming the elavators and up and down lines are also now dead straight, the final trimming (i.e. the throws/weights for snap rolls and spins will be done after the end of the competition season this weekend.

 

Should be competing with it next year.

 

Phil

[John C]

That's great Phil.  Good luck with next year's competitions.

 

John

[John C]

There is a great new build series on this model https://www.youtube.com/playlist?list=PLF09n1avxpLIM_SWVDbLIVbBtJk5YNkTw