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Fauvel AV48

Posted: 11 Nov 2018, 08:40
by Sean Fitzgibbon
Hi everyone,
Thought I'd start a thread to detail the progress on my AV48 from the Vic Steele plan and Sarik Hobbies short kit. I started it at the beginning of the year in our Newent and District MAC clubroom, birthplace of the T21 that Frank, Roger and Andy built a few years ago and also the IS-5 canard.
It features an unusual building method, with formers being spaced along top and bottom keel pieces and 1/4 square stringers added to create the initial shape. It's then infilled with 1/4 balsa, sanded and glass clothed.
I'm about three quarters of the way through the infill process at the moment, progress is steady but as we only attend the clubroom two nights a week for a couple of hours, it's not a quick build!

Re: Fauvel AV48

Posted: 11 Nov 2018, 08:43
by Sean Fitzgibbon
Initial framing.

Re: Fauvel AV48

Posted: 11 Nov 2018, 08:45
by Sean Fitzgibbon
3D jigsaw puzzle!

Re: Fauvel AV48

Posted: 25 Dec 2018, 18:03
by Sean Fitzgibbon
Infill process on the fuz finished, the small area at the rear will be done with blue foam. Brought it home from the clubroom to begin the sanding, starting to build the fins next.

Re: Fauvel AV48

Posted: 07 Feb 2019, 21:38
by Sean Fitzgibbon
Building the fins and rudder assemblies to a point where they can be used to figure out attachment points to the inner wing panels, which I'll start next.

Re: Fauvel AV48

Posted: 28 Feb 2019, 21:55
by Sean Fitzgibbon
Nice session in the clubroom tonight. First of the outer panel box spars in it's jig, next session will be installing the incidence tube.

Re: Fauvel AV48

Posted: 21 Mar 2019, 22:24
by Sean Fitzgibbon
Spars are nearly complete, one more to skin and one to make complete, then I can really get to grips with the wing assembly.

Re: Fauvel AV48

Posted: 01 Apr 2019, 21:36
by Sean Fitzgibbon
Spar construction now complete, first wing ribs added to the assembly.

Re: Fauvel AV48

Posted: 25 Apr 2019, 21:47
by Sean Fitzgibbon
So. What I thought would be a straightforward method to assemble the wing,( no clue on the drawing as to how the prototype was built), proved a non starter!
Once the ribs were glued vertically to the main spar, the trailing edge was nowhere near straight.
New plan is to pin the ribs to the board along their goat portion, glue in the upper rear spar to jig them up and then add the main spar. Looks better at the moment, but won't really know until I can lift a complete frame off the board.

Re: Fauvel AV48

Posted: 26 Apr 2019, 11:09
by RobbieB
Sean, to build the wing onto a built up spar is a perfectly acceptable way to do it - the way most full size wooden wings were built; but it has to be done correctly or you will end up with a wavy wing as you have done. You cannot rely on the mating faces of the ribs all being correct, even laser cut ply. Even a very small difference in angle there will result in a significant change at the trailing edge.

The correct way is to add the root rib followed by the last rib before any change in wing taper and/or start of change in section. You then need to add a thread datum stretched between the two and this acts as the reference for all the other ribs in between - it is very accurate. You will, of course, probably have to modify the front mating face of many, if not all of the other ribs so as to locate them accurately. I do this by carefully wiping them across a piece of sandpaper until they locate - most only requiring one or two wipes, in balsa, anyway.

You then do the same with the remaining ribs out to the tip.

The leading edge ribs are done in a similar fashion, the only difference here is you leave the spruce false LE cut-out in place with a central line marked on it as the guide for cotton thread. Once all the LE ribs and sub ribs are in place these can be removed and the false spruce LE added before the spar is turned over.

IMG_0011_1.jpg
IMG_0001 (2).jpg

Both LE and TE ribs are held in position when ready and secured with a drop of watery cyno - instant adhesion (as are the fingers on occasions!)

Re: Fauvel AV48

Posted: 26 Apr 2019, 19:30
by Sean Fitzgibbon
Hi Robbie,
I agree with you completely regarding the issues of alignment of the ribs! I had in fact been in the process of adjusting individual ribs at the spar joint positions, just felt wrong sanding laser cut edges. Also, because ailerons make up a large percentage of panel, there isn't a lot of trailing edge to sight along. I can't help but think that leaving the ribs whole and perhaps incorporating jigging tabs would have been more accurate.
We have two nights a week in our clubroom until we start evening club flying sessions in a week or two, so I'll soon know how straight it is!
At our last session I even pointed out to Frank Skilbeck and Roger Spragg your build thread because it showed that it can be done that way.

Re: Fauvel AV48

Posted: 07 May 2019, 20:11
by Sean Fitzgibbon
So, after mulling over the rib alignment, I decided to use a combination of methods.
Firstly, the inboard whole ribs were glued to the main spar after their mating faces were adjusted to allow their trailing edges to line up correctly.
Next, the tip rib was glued into position, lined up by sighting a straight edge down the trailing edge.
The tapered aileron sub spar was then cut and the inboard end relieved top and bottom to allow the formed end to fit between the inboard spruce sub spars.
A few intermediate ribs then had their front edges gently sanded to allow their trailing edges to meet the aileron spar.
This has been left to dry until our next club building session, at which time I'll add the last ribs and cut out the aileron parts.
Thanks again to Robbie and Doug who have been great at chipping in with advice, and to my clubmates, who have talked me down off the ledge when frustration was at its peak!!

Re: Fauvel AV48

Posted: 15 Jun 2019, 15:05
by Sean Fitzgibbon
Managed to move things on a bit with the wing construction, port side framework for the inner and outer panels progressing quite well.
Going to build the elevator and aileron next then put all of these part completed sub assemblies to one side to build the starboard mirror image.
I want to have all of the main parts in hand to sort out alignment and attachment issues before I finish the sheeting.

Re: Fauvel AV48

Posted: 15 Aug 2019, 09:57
by steveshep
I have been building the AV48 on and over over a few years. I had similar issues with the wing. I used centre lines on the ribs where they meet the spar ,on the spar and TE to get them straight . It took a while but looks ok . I have yet to attempt to build the ailerons as they will be difficult to keep straight.
I have all the wing panels ready for sheeting .
I cheated a bit on the fuselage and planked the whole thing with 3/32 balsa which was sanded and filled then covered in glass cloth and epoxy.
I still need to work out how the panels and fins fit together neatly!
I will take some photos and post them when I get chance
I plan to carry on the build this winter as I have now completed other projects

Re: Fauvel AV48

Posted: 16 Aug 2019, 07:49
by Sean Fitzgibbon
Hi Steve, nice to hear from another Fauvel builder,. I have to say, your method of sheeting the fuselage is something that was discussed in our clubroom when I began my build! It would definitely be easier and quicker to do than the infill process that Vic designed, but I have to say it works fine.
I haven't achieved much on the build lately, we only have one two hour session a week through the summer. The port side panels are pretty much ready to sheet, but I'll figure out attachment methods first. The aileron was very flexible and not too straight initially, so I added diagonal bracing and cap strips while clamping the trailing edge to a metal rule.
If I was starting this model from scratch now, I'd be tempted to build the outer panels in foam, complete with the ailerons, then cut them free after skinning. Look forward to hearing how you get on!
Sean.

Re: Fauvel AV48

Posted: 26 Aug 2019, 21:50
by Sean Fitzgibbon
So just had a fairly productive session in the clubroom, oiled the plan to reveal the reverse wing panel and marked off the rib positions. Attached the first few, checking for trailing edge alignment and adjusting as necessary.

Re: Fauvel AV48

Posted: 24 Oct 2019, 22:43
by Sean Fitzgibbon
Finally nearing the point of sheeting the wings. Alignment and retention needs sorting first, but close to a trial fit of the assorted sub assemblies.

Re: Fauvel AV48

Posted: 31 Oct 2019, 22:45
by Sean Fitzgibbon
Starting to trial fit the fins, incidence pins and MPX style wing locks will be next, then servos and wiring loom.