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Scottish Aviation Pioneer


Peter  Wood
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Professor

I have added another photo to illustrate a couple of points. Sorry about the confusing background - I will try to take a better shot when I have a bit more time..

The flaps and slats are both fully deployed - you can see them better in this shot.

The main undercarriage is as per plan ie one piece held on by a couple of saddle clamps under the fuselage. In practice there seems to be very little flexing of the wire, the main movement up and down movement in this arrangement being a rocking motion on the 'dampers'.

I have thought of building a new u/c in two halves, each half fixed to the fuselage by longitudinal pivots. However in this case all the vertical movement would be handled by the 'damper' springs and I doubt if they are strong enough.

It will be next week before I can fly again when I will experiment with a more forward c/g and possibily mixing down ele into throttle.

In the meantime I have to find a better way of fixing the cockpit roof. I made the centre section removable and held on by a couple of magnets. However the propwash through the firewall fuel pipe holes blows it off as soon as I throttle up. A few more magnets I think.

Peter

http://forums.modelflying.co.uk/sites/3/images/member_albums/25798/IMGP3953.JPG

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  • 8 months later...

Hi All, 

I've just dipped into the Pioneer post box after a long interval - the automatic flagging up of new posts doesn't seem to have been working. Great pictures.

I'm glad that some "fun" flying is being had.  My own experience with first flights was a bit fraught - CG too far aft because I forgot the slats would need it brought forward, leading to dramatic climbs and extreme pitchyness.  The CG at 25% aft of slat measured total wing chord fixes everything ,and Pioneer becomes very docile.  The ailerons are very poor, but the real aircraft was just the same.  The rudder is very powerful in contrast (real aircraft too) and is needed to do decent turns otherwise the adverse yaw messes things up - no dihedral to help.  I have mixed some rudder in with my ailerons such that full aileron deflection gives 1/4"-3/8" rudder movement too.  This works pretty well.

 Flaps without slats may well cause big pitch changes.  In the real aircraft they are ganged together and you can't have separate action. There are some odd quirks to get through, but I bet the designers of the real aircraft had the same issues.  Pioneer is worth it in the end and I'm still enjoying mine even though a gust on take off caused a big swing and low level hedge entry.  That plus removal of the tailplane when it blew away on the ground during our great Summer!  Easily repaired in both cases.  My undercarriage was too rigid with solid struts which used to bend the fixings, so I built a sprung one after seeing the posts here, which I should have done in the first place.  No problems since, and the springiness of the main leg wire with a bit of compliance from the spring struts seems to work.

All the best,

Chris Reid

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Good morning Chris, I'm a bit slow finishing my Pioneer and would love to see some pitures of the undercarriage you modified. Mine is electric and I had to do some fancy wood working to put the battery in. I made dummy batteries from foam to check clearances. Good job I did because the hatch/former clearance is tight. I'm using a short wide battery that works well. I built a small box to mount the motor, only a half an inch, and have the right spacing for the cowl. I used a steerable nose wheel modified to fit the rear wheel with a push rod to the rudder. Seems to work well and the spring part is in the fuselage so the look is good. I'm in the process of matching the wings to the fuselage then its finishing the wings, lots of sanding and covering and hopefully  a maiden flight early April when the snow melts.

Jack

Toronto.

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  • 1 month later...
I have been thinking about making this model since I bought a copy of the RCM&E Plans Special in December. I have found that I keep reading the article and having a look at the plan, so I'm sure I will get around to having a go making an electric model someday.
 
Anyway, I found this document that anyone building this model will probably find interesting to read. It's the original pilot's notes (manual) produced by the manufacturer.
 
A better resolution copy can be purchased from the webshop on http://www.tailwheel.nl if you need one.
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  • 5 months later...
Hi
 
I was not very clear last time what I'm seeking is clarification for the seating positions.
 
I know there are 5 seats, does it go 1,2,2 ?
 
Middle of winter here in OZ and its prefect weather for flying.
 
Alan
 
Townsville QLD
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Hi Nek,
if you click on the '2 photos' under Chris's picture above it will bring you to an image page and then click on ' 'view album' you will see a drawing layout of the seating and a picture of Chris's finished cockpit. I've asked him where he got the neat seats but he has not picked up on it  yet.
 It might as well be winter here as summer is cold and wet in Toronto.
Jack

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Hi Jack and Alan,
 
Pioneer's seats were constructed from memories of various aircraft I had flown in so they aren't too accurate.  However, I am currently building an Auster AOP9, and have lots of photos of the real thing.  The seats I have made for the AOP9, are very similar to those I made for Pioneer, and are a good likeness of the real thing.  They have two liteply sideplates with balsa sheet cushions in between.  Shoulder harness and lap straps can be made from strips of suitable fabric painted with solarlac or similar, and cut into strips.  I've put a piccy of the AOP9 seats in the album, which may help.  All the best.
 
Chris
 
 
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Thank you Chris, those seats are nifty. I'm still working out an oleo strut for the under carriage. How did you do the wire to maintain the wheel location and still have up and down movement? Could you post a photo of the undercarriage and how it is fixed to the fuselage?  That would be most appreciated.
 
Jack.
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Hi Jack,
 
I've posted some piccys of the modified stuts on my Pioneeer U/C, but they're not too helpful as the construction is largely hidden, and I didn't take any photos when I built it.  I have also attached a mock up photograph of the internals made from scrap bits to give you a better idea of how my strut works.
 
I retrofitted a sprung strut U/C after other folk did a much better design job than mine and showed their efforts here.  My solid strut U/C worked OK but heavy landings tended to bend the strut attachment brackets at the fuselage and wheel ends.  Thus my changes had to fit what was already in place, ie built from the plan.
 
I aimed at introducing some compliance in the spring/shock absorber strut as on  the full size, but without the complication of producing pivoted legs on the aircraft centre line.  The original bent wire V shaped main U/C legs stayed as they were, fixed with saddle clamps at their centre.  I made up two spring struts with concentric brass tubes, the smaller one one plugged with a suitable screw, with a spring threaded up the inside of the larger tube, and simple brass strip brackets soldered in at the ends.  Essentially the ends of the struts were the same as the fixed version, and fastened on to the original design positions.  The strut was sized to enable it to compress about 1/4" after fitting, and needed slight compression to fix in place. The brass tubes were wrapped in appropriately shaped balsa fairings, and some wound paper strip covers to permit the compression.
 
Do they work?  Yes.  There isn't much obvious springing as it's the bent wire legs that do the work, and they don't give much.  However, it's enough that the brackets don't bend any more.  My landings haven't  improved!
 
I hope this helps,
 
Chris
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Hi Chris that was exactly the information I needed now I can forge ahead. I am using commercial struts   Landing gear
 
Product_Name=Shock_absorbing_landing_gear._5mm_(1pc)
I will file them to shape as they are round, what would you think of using say a 16swg wire and letting the strut move more vertically? Would 16swg hold the wheel location given the weight of the model?
 
Jack.

Edited By Phil Wood - Moderator on 05/08/2009 03:53:57

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Hi Jack,
 
The U/C legs you have sourced seem very substantial, and more than up to the job.  My only worry would be that I designed the U/C around the 10swg main legs which bolt on to a ply plate underneath the aircraft  - the whole lot being stressed for landing loads by passing the impacts into ply formers and the airframe.  The springing was the tyres.  All I ever bent in the past was the strut brackets on the largely decorative struts.  If you reduce the main leg wire to 16swg it will become very bendy, and more of the loads will pass into the struts, and finally into the top strut mounting.   The U/C will be much more flexible, but I suspect that in a very heavy landing, you might tear out the top strut mounts, and/or permanently deform the main U/C legs.
 
By all means use the commercial struts, but I would reinforce the top strut mount gussets by using a bigger ply reinforcing plate to spread the loads a little more.  Also, I would use at least 14swg wire, and maybe 12swg wire for the main legs if I reduced the size at all. 
 
I hope this helps.  Let me know how it goes.
 
Chris
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  • 2 weeks later...
Hi All
 
Having flown my Pioneer this weekend after a protracted cosmetic repair I was reminded to look at the this thread. The following comments may be of help, particularly regarding the u/c.
As you can see from the photo I posted I fitted mine with the suspension / dampers designed by Garry Hallam. The main legs were as per plan using 10g wire and secured to the fuselage with saddle clamps. This proved to be a problem.
The initial take offs were fairly exciting until I learned to get the tail up as fast as possible and to feed the throttle in very gently. However after a few flights the plane began to swing unprdictably on takeoff. If I corrected with rudder then the plane would roll very rapidly in the opposite direction as soon as the wheels left the ground often resulting in a cartwheel.
Eventuallly I realised that the saddle clamps had come loose and the u/c was slipping to one side causing the swing. Of course the rudder is so powerful that as soon as the drag from the wheels was released the plane rolled rapidly in the opposite direction.
I soldered brass tubing on the wire under the clamps to give more purchase but it was not really succesful possibly because they are in line with the oily exhaust.
Last Sunday I resorted to hand launching but a spluttering enginde resulted in a heavy landing which severly damaged the u/c.
When I get around to rebuilding it I will have to find a way of controlling sideways movement, possibly by fixing it to the fuselage with brass plates soldered to the wire.
 
Regarding the flying characteristics it is much as Chris described. The ailerons are very weak and induce a lot of yaw. Differnetial helps but the best solution is coordinated rudder. In fact the rudder is so strong that the plane can be flown on it withoput the ailerons if you are gentle. The elevator is OK but the biggest issue is the motor. Mine is overpowered with an OS50 and puts its noe up very strongly under power. Mixing down elevator helps but you then have to be careful not to open the throttle suddenly or the nose will go down before speed increases and it rises again.
Another curious feature is the fact that the rudder and elevator become less effective under full power. I guess the plane adopts such a nose up attitude that the big wing with the flaps deployed masks the tailplane.
 
HOWEVER once you get used to it and find a comfortable cruise setting it looks superb and low slow scalelike passes along the strip always result in admiring comments.
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Hi Peter,
 
I'm sorry to hear you are having gear/take off problems.  My U/C alignment has been trouble free as the clamps fit tightly and prevent any sideways movement.  However, I've found that my Pioneer is very vunerable to cross wind gusts and I've had a few exciting moments with swings during the take off run as, once airborne but seriously off the desired heading, it takes some time to get the bank on and turn back.  Is that possibly your problem?  Aileron rudder mixing helps turns as you've found out.
 
My Pioneer is overpowered too with an ASP 46 two stroke, and I intend to retrofit an ASP 30 four stroke when I get round to it.  There should still be ample power, the big 2S silencer will go, and it will sound better too.
 
When the high lift devices are deployed, the real aircraft has very large trim changes with power.  To control these the tailplane is an inverted Clarke Y type to provide large down forces to create large angles of attack for slow flight.  There is also electrically actuated trim of the whole tailplane from +5 to - 3 degrees of trim.
 
I find that as soon as the model is airborne you can throttle back, or alternatively hold in some down elevator - a bit like my electric gliders.  My transmitter doesn't have throttle elevator mixing or I might have tried it.
 
Still once airborne, and in a stately slow cruise, it really looks the part.
 
All the best.
 
Chris
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  • 1 year later...
Hi Nek.
 
Your post flagged up to me automatically. When I designed Pioneer largish electrics cost a lot more than IC so the thought never crossed my mind. Looking at the drawing this morning, I think it would convert to electric power quite easily. I would use an AXI 2820/10 size motor and 2 x 2200 mAh 3S lipos in parallel as that has become my standard battery pack for larger models.
 
You would need to create a new bulkhead/engine mount in front of the existing F1, but this would be straightforward as it will be circular within the cowl and glue on to the block section in front of F1. The existing F1 could be reduced to 1/8" ply and pierced along the lines of F2, F3 and F4 to permit the batteries to be mounted as far forward as possible, even then some lead might be necessary.
 
Hope this helps. It's a great idea, although the IC motor sound does add to the presence of the model as it buzzes around. When I get round to it, I'm going to retrofit a 0.30 four stroke as the model is over powered on a 0.46 two stroke, and the big silencer detracts from the scale appearance a bit. If you try it, keep me posted.
 
Yours,
 
Chris Reid
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GUYS, John Benham, of LMA guardian fame, designed and built a large scale pioneer, about 110!span, powered by a moki 180, he had fully sprung undercart, working slats and flaps, and the same all over the place on take off problems you have, after advice, he cured it easily, how? he fitted a helicopter gyro, model became a pussycat, worth trying?
 
incidently, he abandoned the leading edge slats as inefective, lot of work for not a lot of reward, John is now retired from flying, but the present owner of the model, Hugh Grant ( NOT the actor ) is flying it succesfully, Hugh is building a monster one, about 1/3rd scale, should be fun,
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  • 3 years later...

Recently decided to build this model, looks fantastic and easy to fly for a learner like me, although plenty of build experience with C/L builds.

I noticed that F7 and F8 were swapped around and didn't notice the sizes were wrong as well, surprised that this hasn't been corrected yet, will correct when I cut the formers.

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  • 6 years later...
8 hours ago, Basil said:

Carlos, just got a copy of the article from Kevin B. Have you built the plane or planning to?.

Do you have a copy of the plan?

Bas

Hello!

As I said, I was beginning to make drawings for my Pioneer, but I was due work transferred to another state and I only finished a couple other projects leaving the Pioneer on hold.  I am unpacking all the stuff I did and hope to restart the project.

As far as plans, I already made some drawings. This will have working slats, I already have another similar airplane (Helio Courier) and when slats are properly fitted, I will do wonders..

Any video of the Pioneer that has been built in the UK?

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