Forum members' new models: Let's see them.

[Peter Miller]

As someone who flew control line for many years (1954-1980+) .  The CG is normally on the front line.  Do not forget the weight in the outboard wing tip. about an ounce or just over.

 

 

Second  in Shuttleworth Scale day

[payneib]

14 minutes ago, Peter Miller said:

As someone who flew control line for many years (1954-1980+) .  The CG is normally on the front line.  Do not forget the weight in the outboard wing tip. about an ounce or just over.

 

 

Second  in Shuttleworth Scale day

I went with the instructions on the tip weight - 1/2oz on 52ft lines. So fingers crossed that should be ok. 

[Peter Miller]

Personally I would prefer a touch more but if that is what the instructions say...OK

[Peter Jenkins]

The other thing to watch out for if your son goes for aerobatics is to avoid using cotton control lines as after a few loops the friction builds up and the controls don't work too smoothly.  Metal lines, the used to be called Laystrait I think, don't get this problem.

[Paul Marsh]

Finished Vq Macchi I got off Martin Thompson . Even had a spare set of Vq retracts and oleos in my electric retract box. Had a 52 in, so fitted a spare .52 and £2 Ali spinner...

[John Lee]

On 23/08/2024 at 15:06, Peter Jenkins said:

The other thing to watch out for if your son goes for aerobatics is to avoid using cotton control lines as after a few loops the friction builds up and the controls don't work too smoothly.  Metal lines, the used to be called Laystrait I think, don't get this problem.

 

Yes, now sold as 'Staystrate' by PAW, who also sell handles & other C/L accessories. https://www.eifflaender.com/price-list

[Paul De Tourtoulon]

Looking at the PAW site, anyone out there converted them to methanol ?

[Peter Miller]

My new model. Value Planes Micro Sinbad. 49" span, 9.3 ounces, vintage glider. Superb kit.Now just need a calm day!?

[Paul De Tourtoulon]

Where is the glider ?.

[Peter Miller]

35 minutes ago, Paul De Tourtoulon said:

Where is the glider ?.

I know, but it is a powered  glider as so many are these days. Even full size gliders have auxiliary motors for self launching.

Anyway....I am too old to run across a stubble field to launch a model.....Stubble field?  Well I can fly this model in the field right across the lane in front of my house.  I have flown quite a few power models there over the years. Eat your heart out!!!!

 

 

 

 

 

 

 

[Peter Miller]

My house taken from my Super Scorpion with a MObious camera

[Paul De Tourtoulon]

32 minutes ago, Peter Miller said:

I have flown quite a few power models there over the years. Eat your heart out!!!!

No you can, this is 12 years old !.

 

https://www.youtube.com/watch?v=vYhLHNvRntE

video 12.docx

[Martin Harris - Moderator]

You appear to have linked to a private video!

[Paul De Tourtoulon]

Try it now.

[Chris Walby]

Now takes you to a word doc with a link that still does not work....

[Martin Harris - Moderator]

[Jonathan M]

My new-to-me Irvine Tutor Mk1, complete with Irvine 46 about to take off for its maiden-for-me flight.  Intended use is as a club trainer, so might have to (for convenience and other factors) convert to 4s electric...?

 

[Jonathan M]

21 hours ago, Jonathan M said:

Intended use is as a club trainer, so might have to (for convenience and other factors) convert to 4s electric...?

 

Or maybe not have to convert to electric... just yet?

 

My main problem yesterday was scary lack of acceleration to takeoff speed before running out of mown patch (roughly 30m long).  I could just about do it by yanking full up elevator inches before the rough grass to get the thing to rotate, then immediately pushing forward to reduce the climb angle to something safer.  I had thought it was simply underpowered for it's weight (hence my thoughts about going electric for more torque) but once in the air the Irvine 46 obviously coped fine (on a 12x6 but now ordered an APC 12x5), and then landing roll-outs were relatively short, just as if there were brakes on the wheels!

 

So the cause seems to be the tricycle u/c:  even though I'd fitted bigger replacement wheels (2-3/4") there's a huge amount of friction/drag in 6-1/2 lbs of model trying to roll forwards on three points on average mown grass, plus the rear wheels are set well aft of the CG making rotation even harder.

 

The solution is to convert to tail-dragger, so I've ordered kit for that, and what a delight it would be to not have to straighten bendy wire after every landing!

 

I don't have a solution to the terrible mess the exhaust residue leaves over half this particular model.... except maybe to convert the motor mount to side-winder, as per my Gangster which leaves no residue at all because the exhaust extension points right down well below the fuselage bottom.

 

 

[Peter Jenkins]

1 hour ago, Jonathan M said:

 

Or maybe not have to convert to electric... just yet?

 

My main problem yesterday was scary lack of acceleration to takeoff speed before running out of mown patch (roughly 30m long).  I could just about do it by yanking full up elevator inches before the rough grass to get the thing to rotate, then immediately pushing forward to reduce the climb angle to something safer.  I had thought it was simply underpowered for it's weight (hence my thoughts about going electric for more torque) but once in the air the Irvine 46 obviously coped fine (on a 12x6 but now ordered an APC 12x5), and then landing roll-outs were relatively short, just as if there were brakes on the wheels!

 

So the cause seems to be the tricycle u/c:  even though I'd fitted bigger replacement wheels (2-3/4") there's a huge amount of friction/drag in 6-1/2 lbs of model trying to roll forwards on three points on average mown grass, plus the rear wheels are set well aft of the CG making rotation even harder.

 

The solution is to convert to tail-dragger, so I've ordered kit for that, and what a delight it would be to not have to straighten bendy wire after every landing!

 

I don't have a solution to the terrible mess the exhaust residue leaves over half this particular model.... except maybe to convert the motor mount to side-winder, as per my Gangster which leaves no residue at all because the exhaust extension points right down well below the fuselage bottom.

 

 

I think that's too big a prop.  I have an Irvine Tutor (also bought second hand) with sn Irvine 40.  That's turning a 10x6 prop.  Acceleration is leisurely but perfectly acceptable take off performance from the smaller of my two clubs where we have about 200 m but a 20 ft tree line to clear at one end.  My irvine 53 used to have 12x6 on it till I put a throttle pipe on it and now turns an 11x9 giving my Wot 4 unlimited vertical performance.

 

Try your 46 on a 10x7 or 11x6.  I'm sure you'll get much more power out of it without causing a noise ptoblem.  

[GrumpyGnome]

I'd echo Peter's comments..... my OS46's, SC46's and Force 46 all use 10x6 or 10/7 and perform well 

[Jonathan M]

Thanks both.  I tried an 11x7 a couple of days' ago but no difference to the t/o run.  Got both 10x6 and 10x7 props in my stash so can give those a go... we're not a noise-limited site but I'd not like to prejudice that by going full Cape Canaveral!

 

30m is not actually a lot of room.  It is fine for the Riot and other leap-into-the-air foamies, but  I'm pushing things with this slightly heavy girl.  The main legs are long, spindly and bendy and the axles keep toeing out (despite an oily bending back each time) so there's a lot of unwanted 'braking' and energy-loss on the ground.  Plus the steerable nose-wheel wobbles slightly and (also despite re-positioning after every landing) veers left at increasing speed which doesn't help!  I can try to tighten the whole setup by snipping off the sloppy z-bend and replacing with a tighter keeper setup, and also rake the main legs forward to just behind the CG to help the rotation for lift-off... but you can see why I'm being seduced by a pair of stiff alloy taildragger legs!  https://www.4-max.co.uk/undercarriages-fixed-40size.html

 

My other club (the one I don't help instruct at but which is now a 1.5hr round-trip) has two 100m smoothly-mown runways and is great for the lighter Gangster - which has shorter, stiffer u/c legs and tight nose-wheel steering so tracks perfectly.

[Peter Jenkins]

If you aren't noise limited you could prop down further to get the revs up.  Max power is around 15,000 rpm so running at 10,000 rpm ish on a 10x6/7 gives scope for trying a 9x6/7.  Aiming for 12 -13 k rpm may solve your problem.

[Jonathan M]

Peter, although we're not strictly noise-limited it is a public space (with the near presence of wild ponies and cows) so I wouldn't want to risk complaints that could impact our long-standing agreement with the council... besides the model is intended as a trainer rather than a tearaway! A min of 11" or 10" diameter will be enough.  This morning I got the motor (and old metal mount) off and nose area clean of knackered nose-leg steering stuff, ready for an upgrade:

• new nylon mount for side-winder mounting (so exhaust residue spits down and as far away as possible);
• complete new 8swg leg and steering arm.

Will keep the trike format for the time being, except that I'll fit the new rigid alloy legs in place of the existing wire u/c, and expect the whole setup to be considerably tighter.

 

Edited August 28 by Jonathan M

[Tom Gaskin 1]

Test flew the model on the left yesterday in quite breezy conditions down here on the south coast. Inspired by Ron Gray's KF2M winged version, it's a scaled-up Hanky Planky to one metre wingspan, allup weight of 533 grammes. My standard foam Planky alongside for comparison.

 

Constructed from B&Q insulation foam by our club's youngest solo flyer, Jake, over his summer holiday.

 

Tom

Edited September 4 by Tom Gaskin 1
Spelling

[Cuban8]

On 27/08/2024 at 20:51, Jonathan M said:

 

Or maybe not have to convert to electric... just yet?

 

My main problem yesterday was scary lack of acceleration to takeoff speed before running out of mown patch (roughly 30m long).  I could just about do it by yanking full up elevator inches before the rough grass to get the thing to rotate, then immediately pushing forward to reduce the climb angle to something safer.  I had thought it was simply underpowered for it's weight (hence my thoughts about going electric for more torque) but once in the air the Irvine 46 obviously coped fine (on a 12x6 but now ordered an APC 12x5), and then landing roll-outs were relatively short, just as if there were brakes on the wheels!

 

So the cause seems to be the tricycle u/c:  even though I'd fitted bigger replacement wheels (2-3/4") there's a huge amount of friction/drag in 6-1/2 lbs of model trying to roll forwards on three points on average mown grass, plus the rear wheels are set well aft of the CG making rotation even harder.

 

The solution is to convert to tail-dragger, so I've ordered kit for that, and what a delight it would be to not have to straighten bendy wire after every landing!

 

I don't have a solution to the terrible mess the exhaust residue leaves over half this particular model.... except maybe to convert the motor mount to side-winder, as per my Gangster which leaves no residue at all because the exhaust extension points right down well below the fuselage bottom.

 

 

Thirty metres or around a hundred feet of runway may well be OK for foamies and certain other models that get away PDQ but your model is pushing its luck with so small a strip IMHO and especially if the grass isn't very closely cropped. From the photo of the model sitting on the ground, the grass is a bit lumpy but far from poor compared to that which many clubs fly from. Is there  a slight upwards incline that might make things difficult on certain wind directions?

My original trainer from over forty years ago was a heavy Hi-Boy powered by a knackered Merco 35 and the usual 10X6 prop - minimal power to say the least but it did lift itself off the deck without a problem  in something like half as much again as your strip. The model weighed in at about  five pounds IIRC.

Are you certain that the Irvine is producing its full power, I'd expect your engine/model combination to accellerate quite smartly - have you checked it with a tacho? I'd guess that the Irvine should be over twice the power of my original old tired Merco, so something sounds a bit odd to me. I'd be interested in getting a reading of the static thrust figure as well.

Give the tail dragger configuration a try, but I wouldn't have thought there would be a significant difference between that and a tricycle in terms of wheel drag (an extra wheel obviously with three v two) to effect the take off run. If the intention was to have the model as a club trainer then the advantage of a tricycle config is lost - also having to keep the tail down during the first part of the take off run will retard its progress somewhat from the start. You mention the main thin wire gear becoming easily distorted and bent out of alignment - maybe an aluminium unit will help with that.

Edited September 4 by Cuban8