Mike Trew Fauvette

StephenB · Post by **StephenB** » 02 Jan 2019, 10:17

As a first scale build since returning to the aeromodelling fold I'm thinking of having a go at the Mike Trew Breguet Fauvette Sarik Hobbies plan/laser cut kit. I'm hoping someone on here has experience of this model and can offer an opinion on the build and flying qualities.

At 3 metres it's a good size for me and I'll use it principally on the slope although I will fit a tow release. I'd want to do the build pretty much unmodified, I have read that Mike Trew aerofoils often get changed but I'd want to leave it as is, which begs the question - does it fly ok? Are there any quirks in the build I should be aware of?

Post by **Peter Balcombe** » 02 Jan 2019, 10:53

Stephen,
I built one a few years back, but changed the wing to have an HQ section (had to thin down the brakes to suit).
All servos were mounted in the wing & tail.
Apart from the wing (I have no experience of the MT section performance), I changed the VTail slightly to fit micro servos in the root end of each tailplane with short direct linkage to each control surface.
This tail mod. worked a lot better than the original pushrod design which had a lot of slop.
The model was fairly light & flew very well.

The fuselage is fairly weak around the base of the tailplanes as there is not a lot of material there.
I glassed my fuselage, but still ended up snapping of the tail a couple of times. In fact it is still awaiting repair from the last occasion.

I will post some photos in due course.
Peter

StephenB · Post by **StephenB** » 02 Jan 2019, 12:51

Peter, many thanks for the reply.

I wonder if the tail end can be beefed up in some way during construction, possibly with carbon? I was thinking of covering mine in Oratex (or similar) which presumably would not be as strong as your all glass version, I've never done a full glass build and I don't really fancy a big paint job, although I could be persuaded.

I look forward to seeing the photos.

Post by **Peter Balcombe** » 02 Jan 2019, 15:04

Stephen,
Some photos of my model.
Yes, you could probably stiffen up the back end with some carbon as only the lower half of the tail section takes all loads.
Issues can therefore occur when there is a high bending load at the front of the tailplane area - e.g. in a ground loop!!

Post by **Peter Balcombe** » 02 Jan 2019, 15:33

By the way,
I have found a pdf file of the HQ wing sections if needed.
I probably just manually adjusted the MT brake design to suit (reducing blade depth & arm lengths) the thinner wing.

B Sharp · Post by **B Sharp** » 02 Jan 2019, 16:07

Hi Stephen. I have a bit of experience with MT plans having built the Olympia (Oly) 463 and the Pilatus way back in the day. I am currently building the MT Slingsby T50 Skylark 4 (check out the current build thread). Peter is right about the wing sections that Mike used on his models. They do work but they appear to be approximations of the full size sections and that is not necessarily a good thing at model size, especially 1/5 scale. Because of the thickness (often over 20%) they tend to be "one speed" so that the wind is often too strong or not strong enough. Both my Oly and the Pilatus were afflicted like that. In addition the heavily tapered wing on the Oly made it prone to tip stall with that profile. On my 1:3.5 scale Oly 463 I have used HQ3.5/14 as my wing section and it has a wide speed range and much nicer stall characteristics.
On my present build I have used HQ3.5/16 at the centre section as the upper surface is close to Mikes profile. This transitions to HQ3.5/14 at the mid-wing break and then to HQ3.0/12 at the wing tip. This should give a more flexible flight envelope. You should also look at replacing the wing joiner arrangement to something more up to date as well as individual servos for the ailerons, etc.
Brian.

StephenB · Post by **StephenB** » 02 Jan 2019, 17:46

Peter, thanks for the photos. I'm very taken with the Fauvette, she's a quirky but (in my eyes) pretty thing and the finish on yours is very well done along with the detailing at the tail. I take it your tailplane is removable for transport - a peg at the front and what looks like a tiny screw at the rear just below where the linkage exits? Yours is a ruddervator, I guess Mike designed it as elevator only with a push rod?

Brian, I was planning to use servos in the wing and probably the tailplane as Peter has done, not really thought of the wing joining system at this point - does Mike use the square blade steel with brass box method? I take your point regarding the wing section, I wouldn't be happy with a "one speed" model, which leaves me with a dilemma. I wanted a fairly straightforward build for my "comeback" model, if I have to modify the wing section then I'm partly negating the need for the Sarik kit so I end up with a plan only project. Which isn't really where I want to be. Mmmmm, what to do ..... In the meantime I'll head over to the build thread and have a look at your Skylark.

Post by **Peter Balcombe** » 02 Jan 2019, 21:04

Stephen,
The MT plan is for a ruddervator Vee tail as I built it.
The only difference in that area is that I couldn't make the twin pushrod drive to the control surfaces work satisfactorily. A picture below shows the original pushrod setup plus the method of attaching the rear of each tailplane half.
As you say, the front attachment is via pegs.

I still have the original MT plan. The wing joiner system is a 12mm flat blade/brass box, plus 10 gauge rear incidence rod which is fine for a 3m span model.

A major issue with fuselage strength is that it is mainly built from balsa. It has mostly laminated 1/16" ply/1/16" balsa formers, top, bottom & side longerons from 1/4 x 1/8" spruce & entirely balsa planked. That is one of the main reasons that I glassed the fuselage - to add strength and surface toughness - but the rear of the end is pretty slim, particularly as there is no strength at the top due to the removeable tailplane halves.
The fuselage side view shows the slimness.

I have included a pic of my brake blades made from epoxy sheet, plus a pic of the wing structure. There are 28 ribs

It is a very pretty model.
Hope the above helps,
Peter

StephenB · Post by **StephenB** » 03 Jan 2019, 08:35

Thank you Peter, very helpful.

StephenB · Post by **StephenB** » 05 Jan 2019, 10:20

A little bit of an update, I've ordered the plan from Sarik. I'll pore over it and decide when/if/how I'll go about it but I'm coming round to changing the wing section. I wonder if the Sarik kit wing ribs would be useable by overlaying a print of the new airfoil and cutting it out of the larger rib profile?