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Author Topic: Show us your P-30's  (Read 61391 times)
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DerekMc
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« Reply #650 on: March 17, 2013, 10:42:47 AM »

The last P30 I built was the Pirate. I didn't use the Fiberglas fuselage because I had a left over rolled Balsa one. Mine is covered entirely with quarter mil Mylar. The torsion rigidity is adequate for P30 flying. My DT system is a bit tough on the wing center joint. If I build another one I would strengthen that part. I use a full pop off wing for DT.

The Pirate is an excellent plane. 29 grams is light! Personally I would add some extra gussets and such to the wing but yours is already covered so get it to weight and have fun flying it.
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« Reply #651 on: March 17, 2013, 11:15:26 AM »

Thank you all for your comments, I agree the 1/4 mil mylar is a major factor in the low weight, and I have no way of knowing whether the torsional rigidity will be 'good enough' as I have never flown a P-30 before... your point is well taken, and I could always add tissue to the wing (over the mylar) to add rigidity if needed. I just covered it as instructed by the plans, so we will see.
I got up early this morning to weigh the individual components, so here goes: The first image is of the Czech prop and hub assembly, it weighs 9 grams. The fuselage with rudder, band burner and battery, pylon, crockett hook, lever and mousetrap weighs 9.75 grams. The wing weighs 7.75 grams, and the stab weighs an even 2 grams. Photos attached.
As I said before, the fuselage being so light was what was surprising to me. I have a pretty deep experience level in advanced composite materials, and I gave two attempts at making a similar tube, one from carbon tissue and one from kevlar tissue with uni carbon reinforcement. Both came out heavier and not as refined as the one that StarLink makes. I really respect that level of build, it's darn tough to do. I could probably get to the same weight and stiffness as the one they sell, but it would cost me quite a bit more in time and materials to do. The pylon is also darn light, compared to my elephantine attempt on the Polecat.

DT

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Re: Show us your P-30's
Re: Show us your P-30's
Re: Show us your P-30's
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Tmat
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« Reply #652 on: March 17, 2013, 11:54:49 AM »

DT,
I have another take on this. Your weight can't be right. I have a Pirate P-30 built from the kit and with all 1/4 mil mylar covering it weighs over 40 grams. I have the Burley band burner timer also and the pop-off wing DT. I know what all the parts of that airplane weigh and it can't possibly come to 28.6 grams! Check your scale. I'd believe 38 grams or even 48 grams but no way is it 28 grams. My stock nose block with Czech prop weighs 11.2 grams. My complete fuselage (same as yours with fiberglass tube and pylon) with pylon rudder and timer weighs 14.25 grams. That's already over 25 grams.
I've seen quite a few of these Pirate P-30's and they are rarely under 40 grams. So something is wrong with your scales!


Tmat
-if not then he has helium in the wings! Shocked
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Dtriano
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« Reply #653 on: March 17, 2013, 12:00:15 PM »

AHA!!!

I found a chunk of lint in the hinge assembly of the scale that was probably hanging it up. I now weigh a 2005 US Quarter at 5.5 grams, can anyone tell me if this is accurate?
So, after the 'Great Lint Scandal', the Pirate now weighs in at 44 grams all up! And my Polecat is at 49 grams, so I don't feel so bad for making it terribly heavy......

Sorry for the false alarm on weights, it pays to check the scales before posting.....Smiley

Now that that seems to be solved, on the Polecat plans it says in the trim notes 'Stab Tilt for Right Glide'. Sorry for my ignorance, but which way should the stab tilt to achieve right glide?


DT
« Last Edit: March 17, 2013, 12:29:37 PM by Dtriano » Logged
Rewinged
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« Reply #654 on: March 17, 2013, 05:38:40 PM »

My scale is only good to 0.1 grams, and I get 5.5 or 5.6 grams for a recent US quarter.

--Bill
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jswain
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« Reply #655 on: March 17, 2013, 06:48:06 PM »

Stone the Crow!!!

How funny DT, I would have blamed the ohause's old batteries or my public school education first Cheesy

I have 5.6g and 5.7g for two different US quarters on my 3-beamer Ohaus so your in the ballpark.

To turn the model "right"  in glide circle pattern the stabilizer is tilted (as seen from behind the model) with the left hand side of the stab tip slightly below the normally seen level stab line and the right stab side tip is now slightly higher.

Now the model will gently yaw around to the right in glide mode. No rudder trim needed.

On a P-30 start with 1/8" difference per side relative to dead-straight level on the stab platform is a good starting point..

For right power/left glide model, tilt the left stab tip higher than right and model yaws around to the left.


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Dave Andreski
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« Reply #656 on: March 17, 2013, 06:55:51 PM »

John, (jswain)
is correct of course.
Here's a simple diagram, somewhat exagerrated.

Dave
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Dtriano
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« Reply #657 on: March 17, 2013, 10:53:14 PM »

Thank you John and Dave, that's what I needed to know, completely helpful. John, I haven't heard that saying in quite a while, had an old Brit buddy who used to say 'Stone the Crows' all the time...Smiley The Ohaus is now running on all cylinders, happy to say. I inherited it from my best friend who passed away two years ago, he was a rocket propellant scientist and many wonderful chemicals danced on its polished platen--

Spent the afternoon rigging the pylon on the Pirate, it uses the band burner with dental rubber attach to the pivot, then back to a turn-around a couple of inches aft mounted to the fuselage (with tension spring in-line) and forward to the lever arm at the front of the pylon. Also in the pictures is the pylon from the Polecat, with viscous Badge timer, tension spring in-line to a turn-around right at the aft end of the pylon, going forward to a tiny carbon lever at the front.

Both pylons are not yet attached, I want to work out the CG and basic trim before I set them on the fuselages. I'm going to set them up just as on the plans, with longitudinal dihedral (I guess most here call this 'decalage'?) and other tweaks to be adjusted in testing, what seems to be a whole new world of info to assimilate.

Thanks again! - DT

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« Reply #658 on: March 18, 2013, 12:52:42 PM »

John, (jswain)
is correct of course.
Here's a simple diagram, somewhat exagerrated.

Dave

Why are we gliding left??
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Tmat
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« Reply #659 on: March 18, 2013, 01:49:47 PM »

Why are we gliding left??
I think the view is from the rear??


Tmat
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Dave Andreski
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« Reply #660 on: March 18, 2013, 02:40:33 PM »

YES,
From the rear per jswain's explanation in reply # 655.
Sorry for the confusion.
Dave A.
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« Reply #661 on: March 18, 2013, 02:44:12 PM »

Reply 655 said:

Quote
For right power/left glide model, tilt the left stab tip higher than right and model yaws around to the left.



So I assume that's why Dave produced the sketch as he did.  I've only flown P30s right/right, as do all the other people I know who fly the class - but perhaps it was just an example of tail tilt. (which it was when I read all of the message Embarrassed)

PT
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Dave Andreski
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« Reply #662 on: March 18, 2013, 02:52:10 PM »

Sorry again!
I should have referenced sentence #3 in reply  # 655.
Dave A.
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sweepettelee
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« Reply #663 on: March 18, 2013, 03:05:16 PM »

Re adding ballast to bring to required or goal weight:
Since you still have pylon to secure, it is my practice to mount them such that the ballast can be in front, not behind the wing.
That is so the wing-to-stab dimension is on the longish side. Glide and stability are likely to be enhanced by so doing.
That is a Bob White rule of trimming during the final build details.  He always put such ballast on bottom of his bodies with red electrical tape.

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Dave Andreski
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« Reply #664 on: March 18, 2013, 03:11:00 PM »

Lee,
Thanks for that little tidbit.
Dave A.
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« Reply #665 on: March 18, 2013, 11:06:00 PM »

D


DT,  et al,
In summary therefore the right stab higher gives a right turn contribution. I have to go by this because I am ALWAYS confused myself.
I also checked a new US quarter in my reliable OHaus scale and it read 5.7 to 5.8.

Ding
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Dtriano
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« Reply #666 on: March 19, 2013, 07:59:21 PM »

Thank you ALL for the great help. I'm going to go back through the resources on this thread about testing and trimming, and come up with a basic plan for the first glide tests.

-DT

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« Reply #667 on: May 23, 2013, 03:16:49 PM »

It's our FF Nationals this coming wet and windy weekend Roll Eyes Sorting out my models to take I realised that I had no spare P30. Probably not a problem with light breezes, but knowing my luck the model would get blown into the crops, only to emerge when the combine harvester got to it Shocked

So, rummaging around in my bits box I found a rolled balsa fuselage I'd made many years ago, and a tail from the John Godden JGP30 design. In another box I found the wings for a RAFF V vintage model someone had given me; slightly oversize and the top tissue covering was so brittle that it split as soon as I looked at it. The 30" span was achieved by re-making the tips with planed down kebab skewers and the upper surface plus underside of the tips covered with 5 micron mylar.

It's grossly overweight, but I'm hoping that it won't matter if it's windy, bad weather is a great leveller Wink I fitted a Tomy as I like the certainty compared with a lighter viscous damper.

Test glides and hand turns in the park revealed a reasonable state of trim, only needing a 1/32" packing under the tail TE. I'm almost tempted to use it in preference to my supposedly best model - we shall see. A few photos are attached.

Peter
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Dave Andreski
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« Reply #668 on: May 23, 2013, 04:18:05 PM »

Pretty cool!
Dave
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« Reply #669 on: May 26, 2013, 04:07:30 PM »

finished at last.....too heavy at 56 gr (prop:15,6 tail:3 wing:17,4 fus: 20)

waiting some spare time to test fly, intended for PGI trim with no wraps......and 4 strands of vintage 1/4 1986 pirreli

no carbon.....
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« Reply #670 on: May 26, 2013, 07:04:40 PM »

Good luck with it. Vintage Pirelli - it should be interesting, especially with PGI and a fast climb.
John
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« Reply #671 on: May 26, 2013, 07:58:25 PM »

hi friends, I'm looking propellers for my P - 30 I advise dosnde as good and compare them. here in Argentina are not obtained. Regards Jose
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« Reply #672 on: May 27, 2013, 12:22:29 AM »

hi friends, I'm looking propellers for my P - 30 I advise dosnde as good and compare them. here in Argentina are not obtained. Regards Jose
Hi Jose.
Here are some web links to p30 type mail-order supplies.
best wishes, john

prop1 => http://www.a2zcorp.us/store/ProductDetailNP.asp?Cguid={B84A184B-D0FC-4399-AD5B-D3D127475E45}&ProductID=3917&Category=ModelSupplies:Propeller
prop2 => http://www.a2zcorp.us/store/ProductDetailNP.asp?Cguid={B84A184B-D0FC-4399-AD5B-D3D127475E45}&ProductID=1516&Category=ModelSupplies:Propeller
rubber 1/8 & 3/16 => http://www.a2zcorp.us/store/category.asp?Cguid={B84A184B-D0FC-4399-AD5B-D3D127475E45}&Category=ModelSupplies:Rubber

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« Reply #673 on: May 27, 2013, 08:56:47 AM »

finished at last.....too heavy at 56 gr (prop:15,6 tail:3 wing:17,4 fus: 20)

waiting some spare time to test fly, intended for PGI trim with no wraps......and 4 strands of vintage 1/4 1986 pirreli

no carbon.....
Are you flying to the 40gm or 50gm minimum weight?
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DerekMc
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« Reply #674 on: May 27, 2013, 07:45:42 PM »

hi friends, I'm looking propellers for my P - 30 I advise dosnde as good and compare them. here in Argentina are not obtained. Regards Jose

Hi Jose, yo puedo hablar un poquito Espanol. Si quieres ayuda para optener helices por P30 envia a mi un mesaje personal en este foro.

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