SLEC / Precedent 1/4 scale Stampe SV4B

Steve Dunne · April 15, 2020

After 9 months in the build, my SLEC / Precedent Stampe is finally finished.
Now I might have to wait a similar time before being allowed to maiden it!
The model weighs 16lb 12 oz, PLUS 24oz of church roof to make it balance as per the plan. To make it balance at the upper rear wing bolts, as per Cymaz and others, it would need a further 32 oz...
And I thought that it would be nose heavy...

The engine is a Laser 180, with a Falcon 20x6 prop to start with.

Comments and advice most welcome.

Steve.

Note access to engine, glow link, fuel feed when the cowl door is lifted.

flight1 · April 15, 2020

All i can say about the nose weight , if you are nose heavy you get to fly again and can remove some lead , tail heavy and the black bag gets used. I have a 1/3 tiger moth (which a stampe is based on) and it balances on the top wing rear cabine attachment.

And I've got to say your plane is looking realy good

Edited By flight1 on 15/04/2020 12:20:45

Nick Somerville · April 15, 2020

Looks fabulous Steve. Well done. Some lovely scale detailing and I am very envious of the super carb access. Mine is a finger contorting exercise when priming from the exhaust exit hatch. My maiden just before lockdown was with a 18x8 on the Laser 180 but having now fully run the engine in, taxiing around the garden, I have switched to a 20 x 6 in readiness of lockdown release.

Was very comfortable flying mine with c of g on upper wing rear bolts. I have no intention of moving it aft. Wishing you the very best when you het to maiden it.

Nick Somerville · April 15, 2020

Btw where did you source the fine looking fella to fill the cockpit?

Steve Dunne · April 15, 2020

Roger's Pilots, formerly known as Pete's Pilots.

Jon H · April 15, 2020

Lovely model Steve, top marks!

Steve Dunne · April 15, 2020

Just been outside to test the engine, unused since I crashed the Inverza two years ago.

Being a Laser, of course, it started first flick! Very easy to prime it through the "door", so hand-flicking is easy.
It's heating up after a few minutes, probably due to lack of airflow on the ground (on a hot day!).

With the Falcon 20x6 prop, it runs at 6700rpm fully open, and idles at 1800.

Any comments Jon?

Steve.

Jon H · April 15, 2020

Seems ok. I get about 6700 on my cheapo hobbyking prop on the 180 petrol. The glow did 6600 on the same prop. I tried another brand..aerostar i think, that was 100revs quicker at about 6800 if memory serves. You are in the ballpack though so i would not be worried.

Often 'slow' props offer more performance than one that revs higher as the revvy one is not really doing much work. The slower prop is taking bigger bites, which creates more thrust and imposes more load on the engine.

Classic master airscrew props are a great example. They rev well, but the model barely moves as all they do is turn power into noise. A menz of the same size will run perhaps 300rpm slower, but it does more work so the model feels like its got more power.

If you want to test it have rummage for an apc 17x6. If you have one fit that and it should rev like mad. 8800-9000 would be expected on that specific prop.

Nick Somerville · April 15, 2020

Very easy to prime it through the "door".

I read that Steve, Grrrr’d and went out to cut a little access that is semi hidden amongst my side louvres. Can now stick a pinky in and prime. It is hinged and sprung to close automatically. Laser engines love a wet start 😀

Bruce Collinson · April 15, 2020

Hi Steve,

Three succinct comments.

I see you managed without the aluminium tube. I’ll put it in the “just in case” box.

I agree with JC, the fence needs painting.

Good job you punctuated the pilot supplier correctly! “Did you jump?” “Yes, a bit ...”

BTC

PS looks bonny !

Manish Chandrayan · April 15, 2020

Lovely Stampe

My two bits, don't be afraid to add the nose weight, it could always be taken off. Those huge wings can easily carry few extra pounds.

How well is the engine baffled? That may be another thing to look at to solve the heating problem

Steve Dunne · April 15, 2020

Bruce - thanks for the comments - I'll sort out the ali tube with you next time at Greenmires.
And I wouldn't dare puncture Roger...

Manish - thanks, the roofing is now being sorted out.
There is no baffling so far, should be some in place over the next few days.

Nick - amazing what you can do with a wet finger!

Jon - Good comments, I have an APC 18x6 hanging around, will try that next time out. Your suggestion to use the 180 sleeve nut was spot on - many thanks.

Steve.

Adrian Hazeldine · May 13, 2020

Steve, I'm admiring your Stampe and wanted to ask whether the red stripes were painted on or were another layer of film? I'm looking to use Oratex but have never painted onto a covering and wondered if it would be a challenge to get sharp edges given the weave in the covering?

Any advice gratefully received.

Adrian.

Steve Dunne · May 14, 2020

Hello Adrian,

The red stripes are 2-pack Oracolor, brush painted onto the Oratex. Note that there is Oracolor for film and Oracolor for Oratex (I think just for colour matching, I don't know).
It needs two coats to cover properly, but then dries very hard, and is fully fuelproof.

I masked with proper blue painters tape, rubbed down hard along the edges. It worked very well.
There was no problem leaking over the weave.

For the lettering I used frisk film masks cut by Phoenix models. They WERE a problem, would not stick to the 'tex weave.
I eventually overcame this by brushing a skin of clear lacquer on first, and let the film stick to that.

Very pleased with the eventual result.

Good luck!
Steve

Adrian Hazeldine · May 15, 2020

Thanks Steve - much appreciated!

Nick Somerville · May 15, 2020

Well thankfully the wait is over and with certain restrictions/precautions in place our club flying site has reopened.

First flights with my Stampe just prior to lockdown and all was well though due to long grass on the wet patch only made two flights. Today it was all nicely mown and I had a chance to really get a feel for flying the model. I made lots of touch and go’s. At take off the model needs a good bit of elevator all the way through to leaving the ground, in the air level flight = just under half throttle. Trimmed like this I have a touch of up elevator in relation to the tailplane. When coming in for landings as the throttle is backed off the nose begins to drop and increasing amounts of up elevator is required to keep the nose level. With my rates at full I am touching down with full up elevator and feel that this is on the edge of being able to hold the tail down to avoid nosing over; though she just hangs in there. All other flight characteristics are great so not thinking c of g needs messing with but I would appreciate thoughts on my comments. Should I just dial in more up elevator or is there something else I should explore.

extra slim · May 15, 2020

all points to being nose heavy IMO

Steve Dunne · May 15, 2020

Finally - lockdown released and back to the flying line!
The Stampe has now had its maiden - it's still in one piece, and the black bags were not needed...

It took off in about 30 metres, without nudging, and flew quite majestically around the field. It seems quite nose-heavy, and needed several clicks of down trim. Roll and yaw needed no trim. It climbs heavily when the throttle is opened, but a throttle > elevator mix sorted that.
Loops were a bit of a struggle, and rolls needed a LOT of down when inverted.

I think that the 20x6 is just a bit too much for the Laser 180, giving around 6700 rpm on the ground. With a 6" pitch, the speed is VERY scale...
I'll try an 18x6 and a 18x8 next time out.

The CG was halfway between the plan location, and the top wing rear fastening screw as recommended on the other thread here. I am going to remove about 12oz from the cowl to move the CG back around 10mm. That will take it almost to the plan recommended position. Who would have thought!

Plenty of pictures here...
Many thanks to Nigel Castle for all these photographs!

Steve.