Topic: 30% Douglas Skyraider - HAS FLOWN

Thought I'd start a new thread on this one.................

Just a short update..................I'm having a meeting with Keith Mitchell (my over 20kg inspector for this project) this coming Wednesday to discuss the project, and go through any design and material changes required by the plan enlargement. Once this has been 'OK'd, I'll be ordering up the 1st batch of wood to make a start on cutting a kit of parts. 1st part to hit the board will be the tail plane, all 72" of it.................followed by the forward fuselage.

Confirmed over xmas, a full retract package is being custom made for the project by Darrell at Sierra Precision in the US. This will take the form of 2 massive twist & turn main units, with scale over centre drag links. A scale tail wheel mechanism using scale actuation, as well as a set of ali wheel hubs with scale hub pattern to fit to 10" tyres I'll be sending him..................all of this lot is due for delivery to me around April.

So.......until I have something worth showing.....................TTFN.

Phil

My goodness    is this another "customer build" or is it one of your own?

BTW. What span, 12 ft?

  Johan

No..................this is a customer one Johan.

Span @ 30% is 180" ...........................

The meeting with Keith went very well..................we discussed all areas of the airframe, and any modifications and changes to wood selections required, as well as hinging, servos, linkages etc etc............The main topics were obviously how to securely & safely mount a 22HP 20lb 400cc engine to the front  , as well as spar design and the methods required to joining the outer wing panels, the stab 1/2's and the 2 fuselage sections. Most methods will be almost identical (just bigger) to what I've used on the B26, so I'm pretty familiar with how it's all going to go together already

All of my suggestions were agreed by Keith, so he's cleared me to make a start as soon as, and he wanting to have a look once the stab is complete, and the forward fuz is partially sheeted................the aim is Haige hall in late February.

So..............I've placed a BIG wood order via Ali to SLEC, as well as 1/2 a rain forests worth of Cyparis from Stuart at Solutions.

Back with news of wood cutting in a few weeks......................

Phil

So..............I've placed a BIG wood order via Ali to SLEC, as well as 1/2 a rain forests worth of Cyparis from Stuart at Solutions.

Back with news of wood cutting in a few weeks......................

Wow! - Once you get stuck into that lot I expect you'll soon be feeling a little saw...



PDR

Wow! - Once you get stuck into that lot I expect you'll soon be feeling a little saw...



PDR

That woodn't be good news.....

Ahem, I think that's my taxi.....


Cheers
Andy

Bit of good news..............

The MASSIVE canopy was one area of the project that was worrying me. Didn't really fancy making a plug for a 1 off.......................

A chap by the name of Mike Emilio in Canada offers plans for a 1/3 scale, 148" span P-51D. Looking at it's canopy, it's a VERY similar in side profile to a Skyraider, so a mail to him soon had a few photos and some overall dimensions to see if it would be possible to cut down the 'bubble' rear section for use on the Raider. His canopy is around 4" too long and about 1" too high for the raider, but nothing a pair of scissors won't sort.............................so looks like I have a canopy source. The front section is a lot more straight forward as it's all flat plate on a raider, so a brass/wood frame can be made up, and flat sheet acetate used for the glazing.



The canopies shown are 31" long, and around 9" high....................

The 10" wheels have also been ordered today, From RS, they are basically steel hubbed, pneumatic trolley wheels. The hubs are naff, but the rubber tyres have quite a nice diamond tread pattern, so couples with Sierra's nice ali hubs, they will look the mutts...............

So..............I've placed a BIG wood order via Ali to SLEC, as well as 1/2 a rain forests worth of Cyparis from Stuart at Solutions.

Phil, can you save the wood shavings.......i need to make a 80" warbird!!!......should be plenty left over .....

this one's going to be interesting to say the least......wish you all the luck mate

dave

lordy lord 180", thats not much smaller than a full size pitts special you may as well get your PPL and start building full size next

Phil,

Why two canopies?..........

you gonna make two Skyraiders now, like, for backup, at the shows.....      

Phil,

Why two canopies?..........

you gonna make two Skyraiders now, like, for backup, at the shows.....

One static fatigue test specimin, one flying prototype...

PDR

One static fatigue test specimin, one flying prototype...

Of course............you de mon!!

Hi Phil,

Lookin' forward to this one. When do you expect to finish the model?

TTFN,
Neil

2 canopies..................coz thats the photo he sent me  ................

Completion..............working full-time as of about 2 weeks time once the 190 has cleared the bench, I'm estimating around 6 to 8 months solid work...............obviously depending on any delays with sourcing equipment etc etc....

Phil

Do you charge by the hour or for the overall job.  If its by the hour you'll be able to retire after this model is finished 

Do you charge by the hour or for the overall job.  If its by the hour you'll be able to retire after this model is finished 

Per job mate.................by the hour  .................not a hope !

You like my way of thinking though 

The operational versatility of the Skyraider was simply amazing......................................

I 'spose that's for kicking the cr*p out of the enemy...............

This is what you call a set of wheels 



They are actually 260mm dia trolley wheels. The tyres are a pretty meaty pneumatic rubber job with a heavy tread. I will be removing most of the tread, and making the tyre a little more 'round' & smooth in profile rather than flat as it currently is. The method is to put the wheel/tyre in the freezer, then once nice and hard, to spin it up on a wood lathe held on a mandrel, and using a Black & Decker power file with a course sanding belt, sand the hardened rubber away until the desired profile it left........simple !

Once thats done, they'll be off to Sierra Precision to be fitted with a nice set of scale machined ali wheel hubs.

      With the amount of ordinance the plane dragged around trolley wheels are a perfect match  :ww

  Johan

We're on the move....................1st cuts have been made today. (1:5 scale 190 fuz in there just to give scale to F1 & 2)



Anyone who knows the Ziroli Skyraider will see I've made major alterations already. The internal ply fuz sides used to end on the back of F1, and an engine box was butt glued onto the front of F1 (good practice ??......NOT !)..............not any more. The internal sides have been moved slightly close together, and now pass right through F1, tying the firewall in with the LE & TE of the wing, as well as the former at the break point of the fuselage.....................these internal sides (the piece the formers are resting on, all 71" of it) are also from 1/4 birch ply, and have an 1/8 ply top and bottom to create the box, going back as far as F3.

The notches to take stringers & longerons will be made once I have picked up the Cyparis on Wednesday morning......................so until next week when I should have a full kit of parts for the fuz.............See ya.

Phil

The Plantation left the store today. You should have seen the look on the DHL drivers face when he tried to pick up the two packages of ply
 I think the F.W will fit in the slot for the engine box.
 Nice wheels. My first car had smaller wheels than that 

The car I have NOW has smaller wheels than that....................    

Phil, this looks prommising, back to the good old wood again  :ww
Can you fill us in on the spec. on this one ? Scaled up Ziroli is it ? engine , make, type aso.

  Johan

Hi All,

Ali; I reckon you could transport the 190 inside the Skyraider fuz They're seriously big lookin' formers!

TTFN,
Neil

I think the F.W will fit in the slot for the engine box.

UUHhhhhh, yea.................quite easily actually  .................

Phil, this looks promising, back to the good old wood again  :ww
Can you fill us in on the spec. on this one ? Scaled up Ziroli is it ? engine , make, type aso.

  Johan

Yea..............I had a very pleasent few hours getting covered in wood dust..............much better for you than glass dust 

The Raider in as you say a 'blown up' Ziroli, outline only really, I'm adding major structural alteraion in again, similar style to the B26 just to cater for the size and load increases. Span has gone from 100" to 180", giving a scale of 30%. The wing in a 3 piece affair, 85.5" centre section with 47.25" outer panels. Length is 136", 91" front and 45" rear. Stab span is 72", split in 2.

Estimated AUW is around the 100lb mark, 47.5 sq/ft wing area giving a VERY light wind loading on only 2.1lb sq/ft

Construction is 100% wood, no glass, not even the cowl. Birch ply, lite ply, a rain forests worth of Cyparis and balsa is as complicated as it gets......there is just a lot of it 

Retracts are custom made from Sierra Precision, and the engine is the new 400cc 5 cylinder 4 stroke radial from Moki/Mackay/RCS (call it what you want) 400cc, 22HP, 20LB weight, swings a 39 x 25 carbon prop at just under 4,000 rpm....................oh, and did I mention the NOISE 

Radio will be SM's Rx Buddy coupled to a pair of JR PCM Rx's, 2 x 15/20kg digi servos per surface (14 servos in total just on control surface) & heavy duty switches and wiring. Batteries................don't know yet............Ali may choose to go LiPo to get a huge amount of capacity, but with weight not being an issue really, BIG Nicads or NiMh won't be a problem either.

Back to it.

Phil

Batteries................don't know yet............Ali may choose to go LiPo to get a huge amount of capacity, but with weight not being an issue really, BIG Nicads or NiMh won't be a problem either.

Phil,

On something of this size it would make a lot of sense to consider an on-board generator and smaller batteries. Does the motor have anthing that you could conveniently take an accessory drive from?

Just a thought...

PDR

Mmmmmm......................thats worth thinking about.

Don't have the engine yet, so difficult to say. It doesn't have a 'rear' crank shaft like a Zenoah, so the only accessible 'rotating' bit is the prop driver, and you have 5 big pots, and 10 pushrods to negotiate to get to it from behind. Could prove an interesting challenge...............

Any one know of such a system being used elsewhere ??

Phil

Like this one :
http://www.sullivanproducts.com/GenesysCustomMainFrame.htm


Kjell

Mmmmmm......................thats worth thinking about.

Don't have the engine yet, so difficult to say. It doesn't have a 'rear' crank shaft like a Zenoah, so the only accessible 'rotating' bit is the prop driver, and you have 5 big pots, and 10 pushrods to negotiate to get to it from behind. Could prove an interesting challenge...............

Any one know of such a system being used elsewhere ??

They're used a lot on UAVs - they guarrantee electrical power so long as the engine's running and usally incorporate regulator/battery management units. The ones I've seen often incorporate an on-board electric starter as well, which might be worth considering, although these normally require "ground power" to be plugged in to power the starter.

Look around in the UAV world.

PDR

Can't see a problem trying to run one of these Phil, look like they could fit quite well.

However it is just something else that could go wrong!!

Doubt you'll be able to do the elec start as the compression will be too great (unless you use a huge elec motor!!)

Steve

Be well nice pressing a button on your TC and watching your engine fire up as if by majic lol

Doubt you'll be able to do the elec start as the compression will be too great (unless you use a huge elec motor!!)

Gears are a wonderful invention. These on-board starters have no trouble firing up 50bph flat fours and sixes at temperatures down to -30 degrees C (don't ask how I know this) - I doubt a wimpy little 400cc radial would be thought much of a challenge.

PDR

Mmmm.......the bigger Sullivan items look quite good, and I agree with Steve that fitting one (or getting one made to fit as they seem to offer that service) won't be a problem......................on the other hand, I also agree it's another thing that 'could' go wrong...................6 of 1, and 1/2 dozen of the other ??.................fit one of these, pray it keep working, and go with smaller batteries, or don't bother, and load the thing to the hilt with on-board power ??.......................

Food for thought.................thanks chaps.

Phil

Phil,

Sullivan's a quality outfit.  Also less than a mile from the house:).  Did you see the starter/gen. combos?  Customer's call, but I'd say it would be very impressive to hit a switch on the Tx and watch that monster chug to life...

Cheers,

Phil

I agree...........go for it Phil.........after all, who's paying......     :ww

Really looking forward to this one.  I love seeing the big stuff being created and flying.  Still working my way up to it.  Still building 60" kits, next one will be 70-80".  Very inspiring, keep it coming.

Mmmm.......the bigger Sullivan items look quite good, and I agree with Steve that fitting one (or getting one made to fit as they seem to offer that service) won't be a problem......................on the other hand, I also agree it's another thing that 'could' go wrong...................6 of 1, and 1/2 dozen of the other ??.................fit one of these, pray it keep working, and go with smaller batteries, or don't bother, and load the thing to the hilt with on-board power ??.......................

Food for thought.................thanks chaps.

OK, let's take it a bit further. A starter/generator/electrical management unit will give you a model that ALWAYS flies with full batteries, and warns you if there's any battery problem. A decent one will have multiple independant outputs, so you could have three completely seperate 6v DC power supplies (busses) for the radio. So you could run (say) the right hand aileron and elevator servo plus Rx1 from Bus A, and the left aileron/elevator and Rx2 from Bus B. The rudder, throttle and ancilliary servos would run from Bus C. A 12v Bus could be used to power the starter, retract units and lighting. A 10cell nicad would provide starter power and backup power for dead stick and/or generator failure. The Nav lights would be wired to the status monitor so that they could flash codes for various different failures, battery low, generator not charging etc etc. Failure of any one bus would leave the others running. Each bus would be seperately fused (or current-limited) so that a failed servo, stuck control surface etc would only drag down that one bus, and you'd still have at least SOME control over the model.

An external socket would allow an external 12v battery to be plugged in so that even if the main battery was flat the model could be started and run for 5 minutes to charge it up, so the model would ALWAYS be ready for flight so long as the Tx was charged.

In fact with a very little extra effort it wouldn't only be safer and more reliable - it would be an electrical system that complied with with JAR-VLA or even JAR-25, which would make CAA acceptance easier and show the way for other models of this size to be engineered.

PDR

[edited because I left out the primary benefit! DOH!!]