Aeromaster

[Martin McIntosh]

I was at a Rochester Airport event in the very early 1970`s trying out F3A and watched Ken B. and Chris Foss doing freestyle with their Aeromasters. I remember thinking at the time, `I hope that guy does not decide to take up F3A`.

They were flying the double sweep version and I got Ken to send me a plan. For some reason I never got past cutting out the ribs; I can only think that F3A got in the way of building it.

A club mate has one with a 61 in it but it appears to me to be a rather smaller version than the ones I watched.

[FlyinBrian]

Posted by Martin McIntosh on 23/04/2020 15:25:39:

I was at a Rochester Airport event in the very early 1970`s trying out F3A and watched Ken B. and Chris Foss doing freestyle with their Aeromasters. I remember thinking at the time, `I hope that guy does not decide to take up F3A`.

They were flying the double sweep version and I got Ken to send me a plan. For some reason I never got past cutting out the ribs; I can only think that F3A got in the way of building it.

A club mate has one with a 61 in it but it appears to me to be a rather smaller version than the ones I watched.

My then club was Gravesend AC who were the organisers of the Rochester model show.

That is when I first came across the AM and my first was built from a plan supplied by Ken. Adequately powered by an OS 61FSR.

[Martin McIntosh]

Do you remember the wingspan?

[FlyinBrian]

Posted by Martin McIntosh on 23/04/2020 19:21:51:

Do you remember the wingspan?

Martin

It can be built in three versions.

Both wings at 48" with the top one swept.

Top wing 52" and swept - bottom wing 48" straight.

Both wings at 52" and both swept.

The plans can be found on OuterZone. see here https://outerzone.co.uk/plan_details.asp?ID=10240

Edited By FlyinBrian on 24/04/2020 13:28:41

[Martin McIntosh]

OK thanks.

Do you know if the plan can be `tiled` please?

Edited By Martin McIntosh on 24/04/2020 14:53:38

[Nigel R]

Isn't the tiling something that acrobat does?

[Nigel R]

I added the hinges for the ailerons.These are polyprop flat hinges and just need a knife slot, I use a stanley blade as it is quite thick and can be snapped to form a chisel shape.

Bevels were put on using one of my hi tech bevel tools:

This should be enough movement I think:

I used thin cyano to judiciously harden up the front edge of the aileron.

Now that all went swimmingly well until I came to make the last, inboard slot. As I slowly wiggled the knife blade through the reinforcement hinge block fell out So much for my normal careful slow building!

Some open heart surgery was needed on the underside of the wing:

In context:

Argh! The air was filled with delightful language for a few moments.

Anyway, the hinge block went back in place and was reglued with 'some' thin cyano. Then the piece of wing skin I had cut out went back in the hole. The wing surface will never be the same again... I filled the hold and sanded back as best as I can but there remains the harder wood from glueing the patch back in. Hey ho.

Fortunately (!) this hole is right on the inboard edge of the aileron, and, after some thought, I realised that I can rescue the situation quite a lot by making the first layer of glass tissue (wing joining) wide enough to cover my sins. And then nobody will ever know. I normally do three layers of tissue with the first being around 10" wide or thereabouts. If I make it 14" wide it covers the patch up - and will help reinforce the inboard edge of the aileron a bit.

One step back, two forward...

[Martin McIntosh]

I too thought that Acrobat offered that normally since I have done it before, so I may persevere with it but am awaiting a reply from a club mate who can normally print off files when he is at work.

I am surprised at your very wide wing joining cloth, I only use about 2" if at all.

[Nigel R]

Martin I only use surface tissue for wing joining not that girt thick cloth that used to be sold in wing joining kits. Tissue or surface cloth adds very little weight.

A nice wide piece of that also does a great job of stiffening up the wing skin making it less fragile and more resistant to ham fisted treatment during transport and assembly.

[Martin McIntosh]

No, I meant even the thin stuff! Good idea though for preventing knocks and bangs.

I realised that the previous tiled plan I did was with an earlier laptop which has a different version of Adobe. It only took about 6hrs to download the s/w for my later wireless printer to an older one. What happened to plug and play?

As I thought, my mate is working from home and has no access to his plotter.

Only about 25 A4 pieces for page 1 of the plan so this should be interesting to do.

[Nigel R]

It's probably not necessary from the point of view of airframes strength and flying loads, as you say. But A careless digit cracking the wing skin does put a damper on the flying session though and a bit of glass works wonders to stop that.

As for printer drivers, file under ain't technology marvellous!

I try to avoid taping the tiled plans together, if possible. I get as far as i can with lots of measuring using the acrobat measure tool. That gets a lot of parts sized right. I redraw wing plans in my own style most times anyway. Curves on formers and so forth, you're stuck with joining a few pages together unless you select a part of the plan to print. I believe there is a way although i forget how.

[Nigel R]

On a side note i bought an hs635 from Ebay. Intending on using it for rudder on this build.

Sounded noisy, on the servo checker.

Turns out the reason it is noisy, is because it is actually a big standard hs322 with a different sticker on.

Amused i was not. Refund i will be expecting. Hmm.

[Martin McIntosh]

On my Mew Gull I just taped together some essential parts. With this one I told it to print with 0.5" overlap which worked on a test piece but when the 25 pages printed they were minus that so a setting must have got lost. Will keep at it.

Regarding ebay servos there has been a lot of discussion on here recently. I too have been bitten by them not being what they were supposed to be so never again.

[Nigel R]

Its a bit of a chore when there are that many pages.

As for faked servos, yes, I usually avoid untested Ebay sellers for stuff like this that is commonly faked. I thought (second hand) a seller with good feedback would be alright. One to chalk up to experience.

I do use a few shops on Ebay, but they are basically proper shops with an Ebay outlet (like Steve Webb).

-------------------------------------

Last night, still on the servo front, but more positively, I refreshed a couple of my old (but fully functional and honest) JR standard servos, by putting a ball race on the output to replace the nylon bush. They should be good for aileron and elevator. I have an old standard HS300 that will do for throttle.

Then I started on the torque rods:

Slowly slowly catchy monkey. This was part way through sinking the bearing tube into the trailing edge. It needed a few more swipes with the circular needle file to fit properly.

And with the fixed section rebated in the same fashion:

I've had to make the arms pop up a fair way out from the centre of the wing. The torque rods were not quite as long as would have been ideal. I guess they were "standard" length (whatever that is) but with the aileron being quite wide, they needed a long arm to poke into the aileron. Result, the spanwise part of the torque rod was quite short.

I must now do some measuring to make sure I don't end up fouling the wing bolt blocks inside the fuselage when it all goes together.

Oh, and, repeat all the above on the port wing.

[Martin McIntosh]

I now have a tiled plan for the wing and fus., 2x 25 sheets of A4 which actually went together quite well considering the age of the plan. I had almost forgotten how inaccurate some of those pre CAD drawings were.

I have not looked at them in detail yet but was surprised to see that you are using torque rods, presumably as per plan. To my mind nasty things with lots of play possible. Why not connect the servos directly to the ailerons?

I shall almost certainly go for a four servo wing as on my Stampe since it saves a lot of messing about rigging the thing and mini MG ones are very cheap now.

By the way, if you are proposing to use old JR 107`s converted to 117`s and happen to be only using a 5V supply I have a few JR 591`s with very little use and no longer need since I now generally use 6.6V (591`s do not work over 5V).

I have a few motor options:

ST 61XRE but this needs a pipe.

OS 91FX.

YS 63S.

YS 110 but this could well be a bit OTT.

Laser 80 which sounds the best bet and the model really needs a four stroke to sound right.

I shall soon be annoying Balsa Cabin with my list of wood and insisting on only the very lightest in most cases.

[Nigel R]

Torque rods do seem quite divisive! Personally I like them. They were indicated on the Aeromistress plan and I believe the Bi Fly used them. The Aeromaster is of an age where bellcranks were standard. I am somewhat mixing bits of all three designs together for my build. I can see why you would use four servos for a build with ailerons all round.

Laser 80 sounds good. Especially if you can build light. The original would have had a crossflow of course. Motors from 45 to 60 size are shown.

I am guessing you have printed the Great Planes updated version? This does seem to indicate bigger motors.

Aa for my servo choice yes, I have a pile of jr 507 standards and i am on 4.8v packs.

[FlyinBrian]

Martin I can not comment about tiling as I used an original plan that I had copied at a local copy shop for about a fiver iirc. If you need large plans printed try and find a local Architect they often have printers/plotters that will do large stuff

I had a Wolfgang Matt "Superstar" done this way but he was a bit dearer at £15

Re motors, a modern .60 two stroke  is more than enough, I use an ASP 91 four stroke in my current model and it suits it well though I am sure it would be ok with a .70 FS.

Also be aware that with most modern motors it will probably turn out nose heavy, I had to put the elevator servo at the rear to avoid adding weight when using the ASP 91 FS.

Edited By FlyinBrian on 28/04/2020 12:00:58

[Nigel R]

The original plan shows;

Veco 45, Veco 61, Supertigre 56 & 60, Merco 49 & 61

all of which would be blown out the water by a modern 10cc two stroke let alone a 91FX or 110YS!

[Martin McIntosh]

I sometimes take mag. plans to a local print shop and get them done/resized on better paper but they are all shut now. My club mate is a structural engineer but currently no access to his plotter so I expect other architects will be in the same boat at the moment.

Strangely the Laser is only a couple of oz lighter than the YS 110 but 4oz lighter than the ST 2 stroke. The cowl will need extending a little for it but I shall be making the whole thing from grp anyway.

Those fus. formers look a little delicate from what appears to be 3 3/32 but I shall probably modify their construction. Quite a bit will be changed such as those 1/2" (!) wing seats and the various mounting blocks. Tail and fin will be slightly thicker and hollow.

[Nigel R]

It's quite beefy on the front fuselage - 1/2" wing seats, 3/16" sides, 5/16" (!) internal sides, there's a lot of timber in that structure.

I'm intending on doing mine with a more normal 1/8" side and a 1/32" doubler, with some reinforcement around the cabane mounting and other key areas.

[Martin McIntosh]

Thankfully they don`t make `em like that anymore.

[Martin McIntosh]

Just ordered my wood etc from Balsa Cabin and would you believe that there is a 2 week lead time due to them being inundated. Great to see that so many are returning to actually building models now.

Probably got time to knock up a couple more mini jets while I am waiting.

Plenty to do though making ribs and formers. One question. Is the top of the fus. supposed to be sheeted or just left open?

[FlyinBrian]

Top of the fus is sheeted with 1/8 th balsa. My H9 kit used 1/8 balsa for the formers.

Edited By FlyinBrian on 28/04/2020 18:14:23

[Martin McIntosh]

Thanks, I just ordered some extra 1/16 for it but have plenty of 3/32 and maybe 1/8th. It does not appear to be shown on my plan.

[Nigel R]

Good stuff Martin. Be interesting to see how you tackle the fuselage in particular and the cabane struts.

I did a little more measuring and rapidly came to the conclusion that my torque rods would foul the fuselage sides. This would clearly be no good at all. Plan A, new torque rods was dismissed as any commercially available rods would be the same size as what i already have. So, plan B was to correct things by moving the ailerons inboard by an inch.

This meant chopping the fixed central part of the trailing edge in two and reseating the torque rod:

That's better. The rod is in a much better location now. Fuselage Sides will not fouled and a nice straight link between servo and torque rod.

Which begged the question, what to do at the tips. My ailerons are now too short. Well, i have this inch wide section of fixed trailing edge doing nothing...

That looks good to me.

Lots of small mistakes on this lower wing. I hope things go better on the fuselage!

More soon.