SAMS Models Lacey M-10

Really well done ! That looks a lot of rubber Andy how much is there ?

Thanks John.

The model required a bit of nose weight to balance the extra rubber for outdoor flight which included a rear bobbin, plus a bit for the added detail at the back end. So the stats for outdoor flying are:

Total weight 208 gm
Added nose weight 9.8gm
Rubber 36 gm (12 strands 20" long of 1/8" tan Super Sport rubber with about 850 - 950 turns, approx 60% max available)
3/32" down thrust
Slight left rudder, slight down elevator
Flight path left/right
Flight time between 35 and 40" in still air (only 20" is required to return a flight score)

Well done, Andy, your faith in the model type has paid off. Very stable and composed flight characteristics - stately I'd say.

It had not occurred to me that the model would need such radically different trim to fly outdoors including a big increase in motor size but I guess the still air conditions and confined space of a sports hall is very different to even the best still air conditions outside. The extra weight would help in moving air to ?

Squirrelnet wrote: It had not occurred to me that the model would need such radically different trim to fly outdoors including a big increase in motor size but I guess the still air conditions and confined space of a sports hall is very different to even the best still air conditions outside. The extra weight would help in moving air to ?

You need to get the model up and out of ground effect when flying outdoors. Also, if there's any wind, you need a bit of extra height to counter the height loss in the first downwind turn. The result is a need for a lot more thrust than when operating indoors. To counter the increased thrust, you need down-thrust to stop the model pitching up. In the case of the Lacey, it needed an extra 3/32" packing at the top of the nose block.

The indoor motor was 4 strands of 1/4" and 2 strands of 1/16" Tan Super Sport, all being 26" long. Motor weight was 18.8gm, a smudge over half that for outdoor flying. In both cases I only used about 60 - 70% max turns (about 900 in both cases). It reduced the initial power burst and led to a smoother flight than if using limiting turns on the motor.

jolly good show, a well deserved win.

Andy Sephton wrote: The indoor motor was 4 strands of 1/4" and 2 strands of 1/16" Tan Super Sport, all being 26" long. Motor weight was 18.8gm, a smudge over half that for outdoor flying. In both cases I only used about 60 - 70% max turns

Great strategising - enough is occasionally enough then...?
Well done again, N

Nigel wrote: ....Great strategising - enough is occasionally enough then...?
Well done again, N

Ha ha. Thanks for the kind words, too!

The 'thrust' statement was first mooted by a colleague when we were test flying RAF and RN Harriers at Boscombe Down in the mid-eighties. It was a real privilege to fly a machine with a greater than 1:1 thrust weight ratio and I can say from experience that in that case, 'Too much thrust was never enough".

Congratulations Andy, a great result. Hope you manage to hang onto your Lacey, I lost my electric version at Old Warden May Fly the other week in a thermal!

Are you going to build an RC version for the Scale Indoor Nationals, could be very successful there as well?

P

Thanks for the kind words Paul - I see that that was your first post here, so Welcome! If you get a minute, please would you consider posting an introduction here:

www.aeromodellers.co.uk/forum/thecafe/10...-yourself?start=1500

As for the Lacey, we intend to build electric, CO2 and IC versions for both FF and RC as part of the development process for the kit. So next year's Scale Indoor RC Nats (SIRCN) may be the venue... I already have a 20" RC version 90% completed. It was destined for this year's SIRCN but life just got in the way. Thinking about it, the 30" may be an even better proposition. After stripping out the rubber motor, prop, bushing and rear peg, I should have about 50gm available for RC gear, motor, hinges and links. Hmmmmmmm............

And the nose block Andy a couple of more grams there .

Picked up the certificate at a BMFA Scale Technical Committee meeting over the weekend.

Well done!
Mike

Beautiful flights, a worthy winner

Ditto, boz.