Flair SE5a restoration

[Geoff S]

Having noted a few threads about the availabilty of Flair kits, specifically the SE5a (ie not available except on eBay or elswhere s/h) I remembered mine hanging up fully rigged in the garage. I was needing a change from my Li'l Cub build so I fetched it into the workshop. It's pretty grubby as it's been hanging there for several years unflown and unappreciated but it was always a very good flyer. I built it over 20 years ago - in fact it was probably the 3rd model I ever built after a Precedent Electrafly and the trainer I used to learn on.

It has an OS52 4 stroke but I'm afraid will be electrically powered when I restore it to flying condition. and the engine will be sold once I've cleaned it up and checked it over.

Apart from its grubbiness I'n quite proud of my build and it's generally quite sound. There are, however, a few design features I intend to change.

1. Top wing fitting is a real pain and takes a lot of time. There are 4 nuts to screw underneath to hold the wing onto the cabanes (they should be srews but I changed them for 4 x 4BA bolts when I built it).

2. The interplane struts attach to the wings with 8 x 6BA nit and bolts into steel plates epoxied to ribs. I made it slightly better by soldering the nuts to the steel plates but it's still 8 screws to fit. Moreover, the steel plates tend to come loose from the ribs.

I've since built and flown a DB 58" ws Cirrus/Gypsy Moth which has a really quick and simple method of top wing attachment as well as an even simpler metod for the interplane struts - I intend to copy them over to the SE5a. At least then it'll be flown a lot more frequently.

I'm going to use closed loop fr the rudder. I'm not sure how the elevators are controlled on the full-size but I'll fit closed loop there, too if that's how the full size is done.

The covering isn't too bad (Solartex) but I'll probably recover most if not all of it. Fortunately there doesn't seem to be much oil. I may try using the stuff Sarik stock and spray with PC10.

The model weighs just under 7lbs as it is but flew well with a 12x6 prop so running on 4S LiPo should be easy.

I'm hoping it will help stave off covid depression which I'm finding myself suffering a bit - I suspect I'm not alone!

Geoff

[Capt Kremen]

My Flair 'SE5a' uses a eFlite 46 power 670 kv turning a 13x8 prop on 4S. (Any similar set up should be fine). Cruises at a 'tick-over'.

Needed a little bit of 'church roofing' material concealed in the back of the radiator to fit the correct C of G.

PS Afraid to electrify it ???? Nay, enjoy reliable electric as it purrs around the circuit.

[Trevor Crook]

Geoff, the top wing on mine is held on by 4 M6 nylon screws that engage in hardwood blocks which I drilled and tapped. Like you, I soldered nuts (M3) to the interplanetary strut plates, but I leave the struts attached to the bottom wing and fold them down, so only 4 screws to fiddle with.

Since mine was built from scratch for electric, it's a bit lighter than yours at 6lb, and flies nicely on about 500W from 3s 4000 packs. The pic below shows the battery box, if that helps.

[Geoff S]

Thanks both of you. Your power suggestions are very similar to what I was thinking. I had thought to fit the battery underneath the motor but a trial fit of the motor I'll probably use (4-Max PO 5055 595kv) indicates that it'll be too low in the engine bay for that but there seems to be more than adequate space above it and Trevor's photo confirms it. I also have a Turnigy/HK G46 - 670rpm/v which I think would also suit.

Despite being very electrical power minded I do like getting my hands oily in the workshop and so I checked over the OS52. It's quite clean (just a bit grubby) and a quick look inside shows everything is oily. I always ran the engine dry and then squirted after run oil inside and that seems to have done its job.

However, there seemed to very little compression so I lifted the rocker cover to check valve clearance. The valves weren't moving at all! I removed the cam cover and saw that the followers were stuck at the top. I took the cylinder head off but nothing would make them move so I removed the camshaft so I could push them out. They were really tight. I've cleaned them up by fitting them in my small electric hand drill and spinning gently against some 600 wet and dry. They weren't corroded but had a very thin deposit perhaps as a result of using fuel with some castor..

They are now a nice sliding fit. I'm not sure if that's right. They will move with a gentle push but won't fall under their own weight. Is that to be expected?

I'll reassemble (just hope I get the timing right - I've checked a YouTube video) and perhaps run it to see if it's OK. I have some Laser Mix 5%, I think, which should serve for a test run..

I quite like playing with engines in the workshop but not so keen when they're fitted in a model

Geoff

[Robin Colbourne]

Posted by Geoff S on 04/11/2020 21:33:28

...I'm not sure how the elevators are controlled on the full-size but I'll fit closed loop there, too if that's how the full size is done...

Geoff

Hi Geoff, According to this cutaway view, and contrary to my expectation, the full-size SE5a used a pushrod to the elevator horn.

Robin

Edited By Robin Colbourne on 05/11/2020 01:05:42

[gangster]

Yes those seem to be common points of frustration. I flew one for years and was up to the covering point on a second which I sold when rationising my fleet to move house. On both I fitter the top wing using those things like wood screws tapped down the middle. As for the struts yes I soldered as well biggest issue was them shaking undone I solved the issue of the plates getting free from the ribs by drilling a hole in the plate and also sandwiching a second piece of balsa the other side the glue acting as a pin On the new one the plates were brass and I was contemplating using pins and little R clips

[Trevor Crook]

Gangster, I'd forgotten the prescribed method of holding the wing on with self-tappers - not good! That's why I used nylon machine screws into tapped hardwood. The threads are still fine after years of use. I used the same method on the kit built i.c. powered example I built many years ago, and it worked well on that, too.

One of the many benefits of e.p. is that, due to the lack of severe vibration, things don't tend to come loose so much. My interplane strut screws are still tight after a flying session.

Geoff, my elevators have a push rod and joiner link setup, which works fine, but if I were doing it again I would try to use a bifurcated rod with a horn on each elevator. Can't remember if the rudder linkage would get in the way of doing this.

[Solly]

Posted by Trevor Crook on 05/11/2020 07:46:13

One of the many benefits of e.p. is that, due to the lack of severe vibration, things don't tend to come loose so much. My interplane strut screws are still tight after a flying session.

Trevor, if you were getting severe vibration with your I/C engine there was something seriously wrong with your set-up.

[Andy J]

Will continue to watch this thread with interest as have a Puppeteer which is a pain to rig, so looking forward to seeing any novel methods of fixing the wing struts and associated rigging wires.

[Former Member]

[This posting has been removed]

[Ted Khinsoe]

Mine stays assembled. Fits in a Megane three door with the tongue just so. It’s Saito powered and has a removable hatch in the floor of the engine bay to access battery and another over the engine for maintenance.

[Geoff S]

Posted by Doc Marten on 05/11/2020 10:53:17:

Posted by Geoff S on 05/11/2020 00:49:56:

I'll reassemble (just hope I get the timing right - I've checked a YouTube video) and perhaps run it to see if it's OK. I have some Laser Mix 5%, I think, which should serve for a test run..

Geoff

Ditch the castor mix from now on Geoff, banish it to the annals of history and stick with Laser mix for a gum free, varnish coat free, sticking valve free future for your engines.

Oh I will (or would if I were to use glow power more often). Bear in mind I built this over 20 years ago when most (all?) glow fuel had at least a small percentage of castor for lubrication. Having said that, the engine seems in remarkably good condition.

How loose should the cam followers be? Should they fall under their own weight? At present they need a little push to move and I'm not sure that's right - they needed a hefty push before I eased them a bit.

Geoff

[Former Member]

[This posting has been removed]

[MattyB]

Posted by Geoff S on 04/11/2020 21:33:28:

...It has an OS52 4 stroke but I'm afraid will be electrically powered when I restore it to flying condition. and the engine will be sold once I've cleaned it up and checked it over.

Apart from its grubbiness I'n quite proud of my build and it's generally quite sound. There are, however, a few design features I intend to change.

1. Top wing fitting is a real pain and takes a lot of time. There are 4 nuts to screw underneath to hold the wing onto the cabanes (they should be srews but I changed them for 4 x 4BA bolts when I built it).

2. The interplane struts attach to the wings with 8 x 6BA nit and bolts into steel plates epoxied to ribs. I made it slightly better by soldering the nuts to the steel plates but it's still 8 screws to fit. Moreover, the steel plates tend to come loose from the ribs.

I've since built and flown a DB 58" ws Cirrus/Gypsy Moth which has a really quick and simple method of top wing attachment as well as an even simpler metod for the interplane struts - I intend to copy them over to the SE5a. At least then it'll be flown a lot more frequently.

I'm going to use closed loop fr the rudder. I'm not sure how the elevators are controlled on the full-size but I'll fit closed loop there, too if that's how the full size is done.

The covering isn't too bad (Solartex) but I'll probably recover most if not all of it. Fortunately there doesn't seem to be much oil. I may try using the stuff Sarik stock and spray with PC10.

Given all that work you can definitely include it in the Dark Nights Fix-Up list - sounds like a great project.

[Trevor Crook]

Solly, by "severe vibration" I meant in comparison to an electric setup. I flew i.c. for over 30 years, and always balanced my props, used decent spinners etc. But I clearly remember the tailplanes on lighter construction models (such as the SE5A) oscillating while the model is on the ground with the engine at idle, probably due to harmonics with that single cylinder piston going up and down, and bang every other rev! A properly balanced leccy setup is turbine smooth by comparison, and things are far less likely to shake loose, although maintenance checks on screws etc. should still be conducted of course.

I didn't intend stoking up an i.c. versus e.p. debate, so to redress the balance I'll confess that my SE5A is about the only model I fly that makes me slightly miss an i.c. engine during flight. Although not absolutely the right sound, the 4-stroke in my earlier example sounded in-character as it flew past. and the thin trail of smoke against a blue sky looked good!

Such a shame the Flair Scouts are no longer available.

[Geoff S]

Thanks, Robin. I've looked at a few pictures and couldn't see any closed loop wires to the elevators so it looks like the full size used a push rod. There are closed loop wires to the rudder and to the steerable tail skid (which I won't bother reproducing)

Matty, I'm just having a brief break from building my Li'l Cub (Peter Miller's design) so I'm not sure when the SE5a will get done. I've given it a good clean and stripped out the electronics (a GWS 35Mhz receiver even!), the engine and fuel tank. It doesn't look too bad so I'm torn whether to strip off all the covering and start again especially as fabric covering is so expensive. I'm looking at Diacov as stocked by Sarik. Has anyone used it?

I've worked out how to install the motor and made a start on the woodwork. I think in different circumstances I'd fit the motor ESC and battery and fly it as is just as an experiment but I'm self isolating mostly and I haven't been to the field for weeks.

The engine is reassembled. The compression still isn't all that good but, if I IIRC, it never was but still ran OK. At least the valves go up and down which they didn't before. I'll try and run it on the test stand before I put it up for sale. There's no rush but selling it will to some extent finance the refurbishment.

A couple of the stringers behind the cockpit are broken and I cut away the covering on the fuselage bottom to examine them. It's a very easy repair. I noticed the 1/4" square balsa used for the framework is hard as a rock and probably very heavy. I think I would have substituted the wood were I building it now but as a novice 20+ years ago I just used the balsa supplied.

Geoff

[Trevor Crook]

Geoff, could you give the covering a really good clean, followed by a re-shrink if required? As you say, it's expensive and if it is sound, a bit of weathering makes it look more authentic.

There's scope for some cockpit detail, I added some instruments and a spare Lewis gun ammo drum to mine.

[Geoff S]

I've been doing a bit more, although we spent most of the day walking into the doctors for a 'flu vaccination and walking a long way back because the weather was so pleasant.

Here's the fuselage as it is now. Sorry for the clutter but it illustrates the cramped chaos of my workshop The covering is quite good and I intend to leave it and add patches to the front. I don't think it's looking like a massive project.

AS you can see, i've removed the covering for the fin. On examination it seemed a bit shaky but once I looked closer I could see the leading edge was broken (a nose over perhaps). The strength was solely down to the Solartex covering - it's strong stuff! Here it is almost repaired. I've added a couple of corner reinforcements and a new rudder post. I'm going to make a new rudder anyway with horns for closed loop and it's as easy to make a new one as the hinges needed to be replaced. Not a major task.

The OS52 was mounted on a Paxolin Or SRBP (Synthetic Resin Bonded Paper) fixed to 2 batten glued to the engine bay sides by 4 x 3mm cap head machine screws. The battens set the downthrust as specified by the kit and theengine mount was angled to give the correct side thrust - quite a lot of both. I'm keeping the thrust angles the same as the model flew fine and the prop doesn't know if it's an OS 4 stroke of a brushless electric motor providing the torque.

This is the bay showing the battens (and the slightly fuel contamination of the wood).

I'm fitting a piece of 4mm ply in place of the Paxolin and using that as the basis of the motor mount. This has the advantage of minimum change so it would be easy to refit an engine plate. Also I don't nave to worry about glueing to the oily wood (IIRC I painted the bay with epoxy when I built the model 20+ years ago)

From this loose assembly you can see there's plenty of room. There's space for the battery above the motor. The ESC will be in the ventilated space below the motor where there'll be a removable cover for maintenance and access.

Geoff

[Trevor Crook]

Geoff, that's exactly where I put my esc, very handy to have the ventilation holes underneath. As mine was built for leccy, it's got a firewall for the motor instead of bearers, but the plan side- and down-thrust have been incorporated.

Even using quite chunky 3s 4000 packs, I've had to add a bit of lead in the nose, but I'm sure you were expecting that.

Your covering does look pretty good in the photo.

[Geoff S]

I've installed the motor and battery.

Here's the motor mount. Because it's mounted on a plate it can all be assembled on the bench.

Then fitted in the engine bay where it's held in with 4 x 3mm cap head bolts. I opened up the former to give unrestricted access to what was the fuel tank bay so I could accommodate various physical battery dimensions.

 

The 4S 4AH LiPo sits on a removable 3mm Liteply plate and is secured with stick-on Velcro (mainly to stop it sliding) and a strap.

There's ample room under the motor for the ESC.

A rough (very) check of the fuselage CoG puts it a bit further forward than needed. However, there's a lot missing from behind it - no rudder and the fin is uncovered, all the servos are out and there's no undercarriage. Never the less it's looking promising and exta ballast will (hopefully) be minimal; can I hope for zero lead?

I've also removed the interplane strut mounts. One of the problems has always been that some of them became detached from the ribs they were glued to, which, quite apart from the faff in screwing them in place, was a pain. Ironically, whilst the ones that I'd had trouble with were easy to get out, it was hard to remove the others, but I managed. I'll detail the new system in a later update.

The ailerons (4 of them) were driven from a single 148 servo in the centre of the bottom wing and 2:1 differential achieved mechanically. I checked the operation with a servo tester and it's awful. Although the mechanical differential works OK, there's lots of slop in the long linkages and the whole thing is very imprecise. I'm amazed how well it worked in practice. While I'm at it I'm going to fit mini servos in each wing. They're metal gear/ball bearing and the quoted torque of each is the same as a 148 so I think they'll work a lot better at virually no weight penalty.

Geoff

Edited By Geoff S on 10/11/2020 19:42:50

[Mike Etheridge 1]

I had to add lead to my SE5A despite it having a weighty SC 52 4 stroke upfront. On the few visits to the flying field I have fixed it together at home as it fits in my car OK

 

Edited By Mike Etheridge 1 on 10/11/2020 21:55:39

[Geoff S]

Mine had an OS52 Surpass and I had a lot of lead, too. I put lead inside the plastic radiator moulding and eventually it all cracked. I was able to get new one and fitted it to a much heavier 6mm ply front part on the basis that if I'm adding weight anyway it might as well be something to make it all stronger.

I've also not been careful to keep the motor mount particularly light and used 6mm ply in places and the motor itself is far heavier than needed so it will all help to reduce the need for ballast. However, I'm sure I'll need some but not as much as before.

Geoff

[Bob Cotsford]

Mine had a 3S 5000mAh pack and about 3oz of lead iirc. I could get a couple of decent flights out of one charge with that pack.

[Mike Etheridge 1]

To add lead on my second hand SE5A, I rolled up two lots lead that I had cut into strips and left holes in the top to take wood screws. The width of the rolled lead was the same as the engine bearers so I was able to fit it either side of the engine and just in front of the engine fixing lugs and fix it with the wood screws..

[Eric Robson]

That's a lot of power there Geoff, mine screams around the sky like a Pitts with a Propdrive 40/48 650kv. I never use more than 1/2 throttle the good thing is I get flights of around 12 mins on 4s, I have a 5055 590 kv in a 9lb Hurricane on 5s and it pulls it round at a good scale speed, only get 6 -7 mins. duration with that one.