Aeromaster

[Nigel R]

Last night's session saw the ailerons, torque rods, and fixed sections, tidied and completed.

First, I cut the port panel's fixed section, and added riblets to fill the end of both sections where I sawed them in two:

I did the same thing with the short bits at the tip.

Next, I corrected a slightly embarrassing error where I managed to build the starboard panel 1/8" too short - I packed out the end with some scrap wood:

That will all be covered up by a nice big wingtip anyway.

Then I filled in the gaps where the torque rod used to move, and made sure the new position had a suitable hole for the arm to move:

And that just about brings it to here:

There. That's much better. The arms are about 1" apart. No fouling the fuselage. The rods from the servo will be nice and straight, instead of pointing outward at 30 deg. The scrap wood filling those holes will be hidden by glass eventually. All is well with the world.

The tips are next on the list. I shall build these up separate to the wing and then glue them on when they are complete.

 

Edited By Nigel R on 01/05/2020 11:05:11

[Nigel R]

I made some wing tip shapes and stuck them to a rib:

They now need sheeting.

They're not quite the exact shape shown on the plan but I've obviously done that inthe interests of making mine look subtly unique As opposed to say, tracing round a handy curved thing.

[john stones 1 - Moderator]

ST 61 in an old flying buddys of mine, went well, made a fair old noise also, throaty.

[Martin McIntosh]

Doing what I can with materials available until the rest of the wood arrives. Since mine will have four ailerons, most of the ribs will start life the same so these have been cut from 3/32 which should be OK. I have made the formers from similar. The plan is way out with these, showing 1/8 sq. then stating 1/8 x 1/4, also some show 1/4 sq. top and bottom but cut to take 1/8 x 1/4. I shall sort them out. I am still not convinced that the rear fus. is sheeted.

I have the balsa plugs ready for moulding the spats and the nose has been basically constructed bar the 1/8 sheet. This will also be moulded. Good way to use up a pile of heavy balsa bought as a job lot.

I had a few pieces of piano wire to hand so have bent up most of the u/c and one cabane strut. (If you study the plan these would need to be made from one continuous loop of wire - hmmm). There is no way that I can bend wire accurately enough to end up with - 1 deg. wrt the bottom wing so I am changing them a bit to give it variable incidence via packing pieces. Photos when done will explain this.

That is about as far as I can get for now.

[Nigel R]

You'll be finished way before me at this rate! I'm taking the approach of having the top wing incidence finally fixed when I set the ply lug piece into the centre section. My wire bending is ok but I'm not sure I can do it with quite that much accuracy, either. I'm doing my cabanes in the style shown on the Aeromistress plan:

the nice thing about that is the top wing then mounts with one M6 bolt.

The cabanes are also be final fixed in the fuselage after covering is complete, the design calls for the crossbracing to be assembled and one joint left unsoldered (to allow for one side to be pulled outward) until it is all together and then the last crossbracing joint is soldered to fix it all in place.

Posted by john stones 1 on 02/05/2020 09:52:31:

"ST 61 in an old flying buddys of mine, went well, made a fair old noise also, throaty."

Always been an OS or Irvine man, old ST were well made lumps though.

Edited By Nigel R on 04/05/2020 14:44:07

[Martin McIntosh]

I cannot see from that what holds the LE in place. Anyway, I shall do mine in a similar fashion to my Stampe which uses four bolts and the strut ends sewn to ply plates which in this case will be span wise.

[Nigel R]

Its an 8" wide ply plate with two lugs that hang down under the LE. The cabanes have a U shaped crossmember at the top front, where the prongs go forward and engage with the ply lugs.

[Martin McIntosh]

OK, I get it now.

[Nigel R]

I got some tips ready to attach last night. The front will simply be made from scrap block.

[Tosh McCaber]

Here are some photos of my(2) Aeromasters. The first, flown in Scotland, before I went abroad. Sold on when we left.

The second, built and then flown in Bermuda, where I worked at the time, then for a good few years in Scotland. Unfortunately, it met its demise when my tranny aileron/ elvator stick came out of the box in my fingers- in the middfle of a low level loop! The wires at the end of the bottom wing were for one-off smoke cartidges.

A great plane to fly- I still have the major pieces in my loft, and am sorely tempted to repair/ rebuild it. Perhaps with electric motor- although I don't know what would be electric the equivalent of the HP61?

Edited By Tosh McCaber on 07/05/2020 10:29:44

Edited By Tosh McCaber on 07/05/2020 10:31:58

[AndyD]

am I right in thinking 7lb is a good weight for the aeromaster,just wondering about weight for my ballerina bipe as it roughly the same size.

[FlyinBrian]

I would say 7lb is fine but it is possible to build down to 51/2 lb if you replace some of the timber in the kit for stuff more closely resembling balsa wood.

[Tosh McCaber]

I seem to remember mine were around the 6lb mark, home-built off the original kit plans

[AndyD]

5 1/2 ib would be a challenge for me as im a heavy builder,just cant get out of the habbit.

[Nigel R]

Love the black and white pictures tosh. Could be a r real homebuilt buzzing the strip.

I'll be very happy if mine comes in under 6-1/2lbs.

You'd probably need about 900w to equal an older crossflow sixty.

[Tosh McCaber]

Thanks for the electric info, Nigel -it points me in the right direction for starters..

The B&W pictures were taken (around about 1975) on the old naval air station in Bermuda. During the war, it was used as a flying boat base, and after, as a refuelling base for BOAC flying boats. Long disused, it was the best flying field that I've flown from!

[Nigel R]

Not much to show for this week's work but the lower wing is near done for now:

First up, prop the tips to the dihedral angle - 3/4" under each tip -and sand the roots vertical. The panels were then joined carefully with epoxy - the gap filling properties are helpful here in case of imperfect sanding. I aligned the tips to remove any slight warp in the panels as is normal practice, fortunately they have come out ok despite the mistakes made during the build. 

Next up was to get the fixed portions of the TE attached taking care to preserve the airfoil and not introduce camber, or get any glue in the torque rods.

I also cut and reglued one of the ailerons to correct a previously unnoticed twist.  

Doesn't sound much but took a fair while to do.

I will next get the usual bandage on over the panel join,  and then put the wing aside until time for rigging, which will be part way through the fuselage build. The tips will then be attached. I think the squared off end will be more use during rigging, easier to align etc, than the curved tip piece. 

Top wing should be easier - dead flat no dihedral and no torque rods.

Edited By Nigel R on 12/05/2020 07:47:02

[Martin McIntosh]

Still awaiting the wood from BC but managed to get some 1/8th from SLEC pronto enabling me to sheet and finish the cowl moulding. Next problem was/is that I am out of suitable glass cloth and so are all of the suppliers but am trying some from SWM to see if I can use it. A huge amount of work in those moulds and everything certainly does not always go to plan.

[Nigel R]

You're doing a glass cowl I presume? Radial, or the original style?

[Martin McIntosh]

Exactly the one shown on the plan, round. I was not aware of another version. Will probably be a nightmare getting the female mould off the balsa plug. Got the first spat half out of the mould today, also the other half mould from the wooden plug. Awaiting materials now.

Mine will be the 52.5" double sweep version so no dihedral to worry about.

[Nigel R]

Of course, the GP version. The cowl does at least taper?

The first version had a basic balsa block type cowl, as per Tosh's pictures.

My thoughts are to put the engine inverted with thrustline a touch higher than plan, and do a basic balsa block cowl around it.

[Martin McIntosh]

Sorry, GP version? It will be from the PDF I got sent. My Laser 80 will easily fit inverted but I have extended the cowl by 3/8" because it is quite a long motor which I pinched from my Mustang. That goes like you know what with it so this model should be fairly lively.

The glass cloth has arrived from SWM, not what I would have picked had I the choice but it is the right weight for the job thankfully. Bashing on.

[Nigel R]

GP = great planes.

[Nigel R]

Last night I got several itty bitty jobs out the way before getting some glass over the wing join.

I dug out a well for the aileron servo with the mini drill and sanding drum. No bearers for the servo to screw into yet, they go on after the glass is done, but, it seemed easier to hog out the hole before the glass was in the way:

and I drilled out the LE to expose the hole where the wing dowel will go:

Looks enormous, but it's 5/16", which is what I have on hand, although I could probably use a 1/4" dowel given that each wing is only holding up half the model.

Anyway, on to the glass reinforcement (not forgetting 1 tape around the torque rods and 2 gloves to stop itchy fingers) - a thin (2" wide) strip went on first:

Stuck on with plain old low tech PVA, it is lightweight glass surface tissue. I couldn't find any lightweight cloth when I bought the tissue. I also ended up with five square metres of the stuff for ten quid, which at the rate I use it will probably outlive me.

Two more layers of this stuff to go before putting the wing aside. The tissue and PVA combination adds next to no weight and doesn't need blending in around the edges, like the heavy thick stuff that comes in 'wing joining kits' which always seemed to me to be more suitable for car bodywork repair than holding bits of balsa airplane together.

With the thick stuff and resin, certainly when I used it, it always ended up with a nice thick lumpy bead of epoxy and glass, at the edges of the cloth, which needed removing with very very careful sanding to avoid going through the delicate and fragile wing sheeting... the evidence suggests I was incapable of the required level of care, resulting in a few repair patches being needed... and lots of filler...

I get on a lot better with 3 layers of thin stuff, no sanding, no large stress points, less mess, film sticks to PVA, etc etc

Edited By Nigel R on 14/05/2020 10:43:27

[FlyinBrian]

The cowl method shown on the GP "Super Aeromaster" is a pain and is not especially strong, mine shattered the first time I nosed over.

A GRP version is available from the states, mine cost $25 plus post. but I expect it will be more now - I do have a spare just in case.

FG Cowl

Edited By FlyinBrian on 14/05/2020 12:09:34