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Author Topic: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)  (Read 853 times)
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Jack Plane
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« on: June 23, 2017, 06:31:53 PM »

I've decided to build a Pacific Ace 30 from the original 1937 plan, so eligible for SAM 1066 Small Vintage Rubber events in the UK.

Its an attractive and well-regarded flier as well as appearing to be a straightforward build, but this will be my first proper outdoor effort so bear with me as I go along if I ask lots of daft newbie questions about things like DTs, covering and sealing for outdoors, braiding rubber, balsa props, rubber-hooks, freewheel mechanisms, etc.

My first instincts are to:
  • cover in normal tissue and dope with 2-3 coats of 50:50 thinned non-shrinking
  • make a removable U/C for ease of transport?
  • use a mechanical Tomy timer (from Mike Woodhouse), and a pop-up tailplane/fin
  • replace the wire rear-hook with an aluminium tube one bay forward
  • make a simple freewheel mechanism rather than use a spring-based or proprietary unit
  • fettle a roughed-out balsa prop-blank (from SAMS) - but what size?

Any encouraging observations or adverse comments?  Smiley

Jon

PS  I've spotted an interesting anomaly in the downloaded plan http://www.hippocketaeronautics.com/hpa_plans/details.php?image_id=765&mode=search - Whereas the plan shows a single lower spar 3/32" thick by 1/4" high, the printwood ribs indicate an upper and lower spar, each of 3/32" square.  Which method will produce a 'better' wing, or is there nothing between them?

« Last Edit: June 23, 2017, 06:55:27 PM by Jack Plane » Logged
DavidJP
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« Reply #1 on: June 24, 2017, 08:03:06 AM »

Nice choice Jon - I have done one for s/c radio (rudder) but not yet had a chance to fly it. A few test glides that look promising.

Have you considered carving your own prop.?  I have done three now and it is a lot easier than you think.  My Ace has a ten inch one which I am told works. 

I can't recall the SAM rules in detail at the moment but if you have not done so perhaps best to check requirements for compliance with the plan as regards spars but pretty sure moving the 'ook is alright. Also removeable U/C - which I have by the way. Probably OK as they are fairly relaxed I think.

I have no D/T of course - a chum rates highly full rudder (about 45 degrees) with his radio version but pop up TP should be fine.  Tomy timers have always worked well so far as I know - Flite Hook have them too by the way and they are pretty easy to put together if you want to make your own. 

I covered mine in (Dilly) tissue and because I do I always apply it damp and that is usually enough to shrink it for the dope.  Again there I have used John Hooks low shrink stuff which when thinned seems to lose most of it's shrinking power!

For the F/W mechanism I have used a Gurami clutch - again from habit really - no doubt others work fine.

The thing I find is that the old methods work well and the modern Gizmos are fine but some of the vets I know still use the basic kit from way back - hand drill fashioned winders - pop up mechanical D/Ts - simple clutches and castor oil based rubber lube. And hold their own very well against modern Kevlar C/F masterpieces from other lands!  J O'D was an example.

So I am sure you will do well with this one.
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Jack Plane
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« Reply #2 on: June 24, 2017, 10:48:51 AM »

Thanks for that detail David.

My 1937 plan shows diagonal bracing only as far as the cockpit, but the various American (kit-built?) examples out there show bracing all the way to the tail - see piccies below.

As long as I don't fall foul of the vintage rules here, I'm inclined to follow Pat Dailey's scheme (last piccie) which does this, as well as housing the rear-peg nicely forward for good clearance.

The complete American printwood kit available in America, which does this, has a different plan drawing.  There's also the Belair short laser kit available here based I think on the sparser 1937 plan, but at £30 plus £10 postage for just a few ribs and some nose formers I might as well just build the whole thing off plan!

Attached files Thumbnail(s):
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
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RalphS
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« Reply #3 on: June 24, 2017, 02:05:46 PM »

Hi Jon - some jottings.  I haven't looked at the full plan so some of my comments may be covered.

Looks like no decalage adjustment.  The zero/zero mounting isn't a good idea.  Consider glueing the fin to the tailplane to achieve adjustment.  You will need to attach the back end bits with rubber bands for a d/t anyway.

Use dowels across the fuz for wing band attachment.  Rubber bands around a fuselage to attach wings are difficult to apply and you will need keys to make sure the wings sit in the same place every time.

9/10" prop should be ok.

Strengthen and modify front end to allow for removable nose block for thrust line adjustment and allow for use of a winding blast tube.

Try covering with mylar or tissue over mylar for tougher, wet resistant covering.

The photos show that others agree with some of the above.

Apart from that - no problems  Grin

Ralph
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Jack Plane
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« Reply #4 on: June 25, 2017, 09:03:54 AM »

Thanks for the input Ralph.

Yes, I did wonder about the decalage issue, but assumed that's just how they flew?  I did think about adding a very nominal amount of wing incidence (if that's not a departure from the rules).  In fact one can just about see a bit of packing in the last photo below of Pat Dailey's PA.

For comparision:  the KK Senator and the Blackpool Rock both show positive wing incidence built into the upper longerons, whereas the Korda Victory and the Lanzo Cabin show none, the latter two being pre-war designs like the PA, which is however the only one to have a flat-bottomed wing section.

How does one apply Mylar?  If tissue-covered on top, then how much of what dope?  If just Mylar, is it available in colours or does it have to be sprayed?

Jon
Attached files Thumbnail(s):
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
« Last Edit: June 25, 2017, 09:27:47 AM by Jack Plane » Logged
RalphS
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« Reply #5 on: June 25, 2017, 10:14:11 AM »

Lots there Jon
Yes, I did wonder about the decalage issue, but assumed that's just how they flew?  
Probably elderly design principles.  Many early US scale models show no decalage.  I don't understand how they fly.

I did think about adding a very nominal amount of wing incidence (if that's not a departure from the rules).  In fact one can just about see a bit of packing in the last photo below of Pat Dailey's PA.
Might be a good idea to read the rules thoroughly Wink

For comparision:  the KK Senator and the Blackpool Rock both show positive wing incidence built into the upper longerons, whereas the Korda Victory and the Lanzo Cabin show none, the latter two being pre-war designs like the PA, which is however the only one to have a flat-bottomed wing section.
If you want to compete rather than just fly, the Senator and Blackpool Rock are likely to be better fliers.  They have better wing sections and the Senator even has turbulated wing. 

How does one apply Mylar?  If tissue-covered on top, then how much of what dope?  If just Mylar, is it available in colours or does it have to be sprayed?
Too big a topic to tack on here. There is info on this site, probably in the workshop section.  Users often vary in how to do it.  There must be users from the freeflight duration competition fliers in your area.  Have a chat.  5 minutes talk can cover more than 5000 words Grin

Keep up the good work.

Ralph


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Jack Plane
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« Reply #6 on: June 25, 2017, 11:36:06 AM »

Nice one Ralph.

I wish to build and fly really just out of interest, but would also like the Pacific Ace to be legal for SAM contests so I can join in for the fun of it...

... even if the Senator and Blackpool Rock are known as much better fliers!

My original plan was to build the KK Competitor - such a lovely looking model aircraft - but haven't found anyone yet who hasn't trashed its performance in the air.

When I'm older, I might even try a P-30.

Jon  Smiley
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Jack Plane
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« Reply #7 on: June 26, 2017, 05:21:49 AM »

Might be a good idea to read the rules thoroughly Wink

I've now read them.  My changes are minor and, as far as I can tell, well within the rules, and none will effect the flying performance in the slightest... except adding decalage by way of a shim!

As the lone whippersnapper in a diminishing special-interest class, it would be a hard CD who'd exclude my model for adding a bit of diagonal bracing to the rear fuselage!  Cheesy
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DHnut
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« Reply #8 on: June 26, 2017, 06:18:10 AM »

Jack,
        I have a Competitor that is a fine flier. It is reasonbly light and will do an easy 2 min plus and looks really nice in the air. I suspect if it is allowed to get heave it might be a real dog but what does not when the weight gets out of hand.
Ricky 
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DavidJP
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« Reply #9 on: June 26, 2017, 06:59:53 AM »

Jon, I took a chance and flew my 'Ace yesterday - was 13/14mph gusty breeze apparently at Sculthorpe and it went surprisingly well considering it was untrimmed save for guesswork - just a little nose heavy but curiously Flyboy said that about his.  I only put on about 400 turns but it has promise.  The radio was on the cg and should not have had any influence.  Using the rudder I was able to kite it up a bit on the breeze.

I did not add any diagonal bracing to the fuselage. Maybe I should have for ballast and left the 'ook in the original position?  Following advice form a boffin chum I used 12 strands of  1/8th - 30 gms - some of these chaps go by weight for a motor not so much the length and number of strands.

On mylar there are various tutorials on the 'net - I don't think it comes in colours but there are some sprays you can buy that are translucent colours.  I have tried it and made a mess frankly.

You iron on the mylar.  I used diluted pva left to dry and mylar will heat shrink slightly but you need to get is as taught as possible.  The idea is you put on a coat of dope and whilst that is still wet lay on dampened tissue and add another coat of well thinned dope but my problem was that I just could not eradicate the blushing that occurred. So gave up for another day. 

Everyone seems to go for a Senator at some time - I have seen some Competitors fly very well and they are far more elegant.  I am a bit squeamish when it comes to rubber motors - they look so butch in such delicate models. But incredibly the model is man enough! I saw someone flying a Gypsy at OW a couple of years ago and the motor looked like a bungee for a Gigante!   
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Flyguy
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« Reply #10 on: June 26, 2017, 12:32:28 PM »

Nice to hear of some flying with your PA David! I really like mine, it's rock stable in the air and a very consistent performer, always fun to fly, a great design. Can't help but post the link to one of my favorite PA flights  Smiley   https://www.youtube.com/watch?v=SO9JVdZKrdY

Jon - my two cents after building the 30" version: mine needed some tail weight. I used a 9 1/2" gizmo, which I think is great, but next time I'd use a 10" balsa prop, that saves a few grams and should cancel the need for any added tail weight, and light weight is all important, plus my bias is that you need a balsa prop for optimum performance. I'd also keep the cross braces, the added stiffness is more than worth it, especially when winding to high torque (and I needed tail weight anyway). I also had to move the rear peg up slightly from where it was shown on the plan (so I could get my half tube in), but I always try to keep the rear peg as far back as possible. You can see the location in the attached photo as well as the cross braces. I also built the 20" version and that was rock stable. I'm thinking of building the 40" version.

Have fun with it, looking forward to the build!
Attached files Thumbnail(s):
Re: Pacific Ace 30" (for SAM 1066 Small Vintage Rubber)
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Jack Plane
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« Reply #11 on: June 26, 2017, 05:33:10 PM »

Hi Ricky - lovely to hear that about the Competitor...  I may well just build one yet!

Well done David for chancing your Ace to the skies.  I paid no real attention to outdoor 'cabin' duration until my son and I flew the little Sparrowhawk we built together - as you know - but now I'm captivated by the sheer magic of it.  Thanks also for relating your experience with mylar.  I'll do my research fully in due course, and might even think about investing in a little spray-gun rather than applying old-technology over new?

Cheers for that detail Flyguy.  I watched your video(s) on building the Pacific Ace et al, which are really useful, and that last one you linked to put a huge smile on my face!  Cheesy

Jon
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Jack Plane
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« Reply #12 on: June 26, 2017, 05:35:58 PM »

PS David, Flyguy...

Did you build yours with zero decalage as per the plan, i.e. with no incidence to the wing?  If so, could that explain why you experienced them as 'nose-heavy'?
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Flyguy
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« Reply #13 on: June 26, 2017, 07:06:53 PM »

It's pretty close to zero as shown on the plan. You can easily shim the wing if you have to. I trim a little different than others in that the last thing I ever do with a plane is add weight, to me that means I didn't build it optimally, though on the next build I know what to lighten up. The first thing I usually try, if it needs nose or tail weight, is to reduce/increase the wing/stab incidence, depending on the plane. You also have to take it easy with the wing incidence if you want the rocket climb; I've noticed that all the long-slow climb videos have slight stalls after launch (=losing altitude), that won't work with the fast-climb approach. Again, I think if I simply change to a balsa prop, that's about a 3 gram reduction in weight, and I had to add about 3 grams to the tail, so bingo - perfect balance with no added weight. So I think the wing incidence is close to optimum, you get an incredible climb during the burst.
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RalphS
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« Reply #14 on: June 27, 2017, 04:00:46 PM »

you get an incredible climb during the burst.

A bit like a VIT equipped rubber model that has reduced negative on the stab during the burst to stop the model looping.  Unlike VIT models how does the cruise and glide compare with similar models that have a bit more decalage?  Where does the model balance?
Do you get away with very little down-thrust?

I have been impressed with your models and amazing thermal flights from that sports patch in Manhattan.  I appreciate that rc helps you get the model back but, what sort of wind strength can the models cope with?  Have you flown in Central Park yet? 

Ralph - an early admirer
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Flyguy
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« Reply #15 on: June 28, 2017, 05:46:51 PM »

Cruise and glide are fine compared to my other models, sink rate is about 2.5 ft/sec. Model balances at around 50% if I remember correctly; all my models generally balance in the 50-80% range. There's about 4 degrees down thrust, maybe 2 degrees right thrust. I just checked my 20" PA and it also has zero on the wing, as shown on the plan, so I think I'd stick with that, you can always shim later.

I can fly up to about 10 mph winds. I've had days where the plane actually went backwards from the gusts, in that case you have to make a diving turn to get it back. Central Park is on my flight list this year, I've scoped it out and both Sheep Meadow and the Great Lawn are huge (a few acres) compared to my current tiny field.

Thanks for the feedback Ralph, I'm glad you enjoy the videos, rubber with RC is really fun, the hard part is overcoming the hurdle to try it in the first place  Wink  But if I can fly a Wakefield in a 1.3 acre field, then you can probably fly any rubber job in almost any local field. Larry
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« Reply #16 on: June 28, 2017, 08:17:33 PM »

I think Larry's approach of aft CG and low longitudinal dihedral is the way to go - if you need any convincing after seeing his scorching climbs on the burst.

It's an integral part of PGI trimming which has been very successful.

Thus build it as per the plan would be my recommendation as well.

John
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DavidJP
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« Reply #17 on: July 01, 2017, 06:55:38 AM »

Yes go with that - mine is as per plan as regards incidence and the climb was noticeable but not exciting because of the wind which it seemed determined to fly steadily into, and it had no more than 400 turns at most! However the nose did drop as soon as the power came off and I could not hold it into wind with just rudder.  But it is my conviction that FF models do fly better when left alone. So I am going to add a little tail weight to bring the CG back to about 50%.
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DavidJP
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« Reply #18 on: August 06, 2017, 05:27:46 AM »

Have had further sessions with the PA and strangely it was a pig in calm air.  However ther were some boffins on hand who suggested more down and right thrust - the latter a bit odd as it was turning right any way.  However I did try it and it is now getting sorted. So will be giving it further flights soon I hope.  The side and down thrust is quite substantial by the way - eighth sheet packing chamfered to zero.
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