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Aermacchi MB339

PSS (Power Scale Soaring) scale jets for the slope.
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Aermacchi MB339

Post by Dave Cooper »

Hi all

At a recent club auction I picked up a PSS Aermacchi which I think is the MB339 (trainer ?) version. Anyway, it has twin cockpits and is made of EPP - so, should soak up the punishment I will probably give it !

It weighs around 2 lbs. (with servos /without LiPo) I was wondering what sort of wind strength I would need for it to fly reasonably well ? Span is approx. 51". Controls : Aileron and Elevator

I also bought a ducted fan unit at the same auction. Given that I'll probably need some ballast near the CG for extra wind strengths, I was wondering about installing that now. Looking at the formula for "Fan Swept Area" etc, I think the jet inlets maybe a little too small and may even be 'under-scale' as well.

If there's some PSS experience around on the forum I'd appreciate any help. If this project is successful, I'd like to tackle something more ambitious...

Merry Christmas,
Dave
Martin G
Posts: 82
Joined: 18 Mar 2015, 13:27
Location: North Wiltshire

Re: Aermacchi MB339

Post by Martin G »

Hello Dave,
2lbs and 51" span sounds like it will have quite a light wing loading for a PSS model.
On a good slope I would guess it should get away in anything over 12-15mph wind.
Come and join us sometime at a PSS meeting (maybe on the Great Orme) next year to have some flying fun and get some inspiration for your next project.
Martin.
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Re: Aermacchi MB339

Post by Dave Cooper »

Hi Martin - that's good to hear....we quite often get winds of 12+ on our local slopes (especially in Winter).

The Great Orme sounds interesting - as you say, maybe in the New Year.

Merry Christmas,
Dave
jack
Posts: 91
Joined: 20 Mar 2015, 21:55
Location: chepstow,south wales

Re: Aermacchi MB339

Post by jack »

As l received a flite test kit of an f4u-corsair this crimbo,l believe l will turn it into a pss model.....l have a horror of el****tric models as a result of my unreasoning dislike of lipo cells,so this seems like an acceptable option,but l suspect that ballast will need to be carried as this model will weigh next to nothing (its built from foam board) :D :D :D
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Re: Aermacchi MB339

Post by Dave Cooper »

Jack - LiPo's can be quite finicky, but, if you follow the 'rules' they are ok (generally). It's the 'short-cut' methods which seem to cause the problems...

What weight is the F4U ? You may need a bit of church roof there !
Dave
ps will post some photos of the Aermacchi when the refurb' is finished.
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Re: Aermacchi MB339

Post by Dave Cooper »

Hi All

I have a 'broken loose' rear pilot in the Aermacchi. The canopy is very firmly attached and, I think, will have to be cut away to secure the pilot's head and shoulders. May add a EJ seat to add a bit of extra stability.

As the fuz is EPP, just wondering what's the best adhesive to re-attach the canopy (and the pilot for that matter) ?

Hoping to keep the (one-piece) canopy in-tact throughout the whole fiasco....
Any ideas welcome,
Dave
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Re: Aermacchi MB339

Post by Dave Cooper »

Just tracked down the previous owner of the Aermacchi - he says that UHU-POR was used to secure the canopy. Apparently, this is the best stuff to use on EPP as it doesn't set 'hard' but gives a good secure fixing.
Dave
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Re: Aermacchi MB339

Post by Dave Cooper »

UHU-POR certainly did the job and was also very useful for other minor repair jobs around the airframe.

Just got the wing refurb' to finish now and it'll be ready for a flight or two.

Can anyone help with posting an image - I usually upload via "Imgur" for hosting (800 x 600 OK ?). I have put the "Frecce Tricolori" aerobatic team orange flashes on the tip tanks to aid my poor old eyes !

Dave
Dave Cooper
Posts: 47
Joined: 26 Sep 2018, 10:42
Location: South Cotswolds

Re: Aermacchi MB339

Post by Dave Cooper »

Thanks Barry

Just a bit more tidying to do on the wing and we should be there ! Size will be straight off my phone as a JPEG...

Regards,
Dave
Attachments
Aermacchi MB 339.jpg
Barry_Cole

Re: Aermacchi MB339

Post by Barry_Cole »

We have a photo!!!

BC
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