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PICA Spitfire 1/5 Please Help

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PICA Spitfire 1/5 Please Help

Old 10-07-2004, 08:48 AM
  #1  
spitty
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Default PICA Spitfire 1/5 Please Help

OK Friends,I´m now a lucky Owner of a PICA Spit ( 1/5 ),and would be more than happy,if You could answer some of my Questions ( I know TOM,I have to finish my P51B at first , but I think before I die I will start with the Spitty)

- I ´ll try to get the tail as light as possible,the wood needs to be changed ( very heavy) cause I checked the MAC or CG in the
middle section of the wings,it´s by 22.35 % !!!!!!!! ( so the plane MUST fly , but will have a tendency to noseover ( i know these
from my other Spit )

I will do a scale ( glass ) finish and some details , so I would be happy,if the weight of the plane doesn´t exeeds 20 pounds...

a ) Do You think a Laser 180 or a Super Tigre 195 will be okay ( I would prefer the Laser cause of it´s small exhaust)
b ) Which Retracts should i use ? ( planning Shindins )
c ) Building Tips ( maybe strongener some areas ,like retract mounts / ribs ?)
d ) Are the outlines of the front section of the fuselage really scale ( I´m not sure )

Thanks in advance and by the way a nice link,they will sell worldwide and have very nice Cockpits, Spitfire Compass....
worse a look

http://www.scale-specials.de/

Thanks in advance
Andy
Old 10-07-2004, 09:26 AM
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Moggy
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Default RE: PICA Spitfire 1/5 Please Help

Spitty

I think you will be hard pressed to get this bird in at around 20lbs or less, especially if you plan to glass it and detail it. I'm not familiar with the engines you posted but I am running a Sach's 3.1 and a G-62 in my other one. Shindin retracts are a good bet just make sure the struts are long enough. Make sure you tell him what size you need becasue the struts for the Taylor are too short. Anything you can do to lighten the tail will help minimize balast in the nose. The later kits should have lighting holes in the stab and elevator. I have 3lbs of lead in the nose and my CG is 4.5 inches from the LE at the dowel. I moved the gear (Robart) up toward the LE to minimize nose overs and beefed up the ribs with light ply. I also used maple blocks for gear mounts.

The Pica Spit is fun scale, It would take alot of work to get it true. The wheels would have to be 5" not 4 or 4.5 and the wing tips and stab are way too thick. The fuse is off as well, so in my opinion, this would not make a good scale project. Just fly it and have fun, they fly well and look good enough in the air. Good Luck, ole Chap and beware of the Hun in the sun.
Old 10-07-2004, 10:29 AM
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Gremlin Castle
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Default RE: PICA Spitfire 1/5 Please Help

I would agree with MOGGY especially about the aft section building too heavy. If I were doing it over I would eliminate about 1/2 the structure aft of the wing and use contest balsa for the tail feathers.
While they aren't right on scale they are excellent flyers if they are built straight and properly balanced.
Old 10-07-2004, 02:51 PM
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Moggy
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Default RE: PICA Spitfire 1/5 Please Help

Spitty

I apologize for the Hun slogan, it was meant in more of a historical context with the Spitfire.
Old 10-07-2004, 02:57 PM
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DaddySam
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Default RE: PICA Spitfire 1/5 Please Help

I'd also agree with the above posts. I did all the "new" lightening procedures, cutting holes in the balsa empennage center sheets, but I did not use lighter balsa. If I did it again, I'd definitely make rearward formers out of balsa and be very careful with wood selection. Even then suppose you save 3 oz of weight? I saved all the wood I cut out in a bag, and it didn't seem to weigh that much. I think if you plan for as much radio gear, batteries, etc. up front, and then use a heavy gas engine, you'll still have to add some lead. I don't think I've heard of one of these (that has flaps and retracts) that has come in under 24 lbs. I recall the box indicating that a .90 to 1.2 two stroke was recommended. I first installed a ST 3000, and after reading a few reviews, switched out to a G62. Now I'm putting in a 3w-50, and although there will be some cylinder and spark plug sticking out, it won't be much, and I still plan on 3-4 lbs of lead when I balance.
These planes have long fuselages and short noses, and the real ones had large heavy engines to make them balance.
Hope this helps.
Sam
Old 10-08-2004, 09:57 AM
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spitty
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Default RE: PICA Spitfire 1/5 Please Help

Moggy,no problem with that.
Funny,a lot of the nongerman guys likes the Focke Wulfs,Messerschmitts and so on, I love the British and American Fighters ( Battle of Britain )
Thanks to all for Your nice Replays,think I will go with the Supertigre,much Power and fits within the Cowl.
Any more Ideas are welcome
Regards
Andy
Old 10-08-2004, 08:52 PM
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Moggy
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Default RE: PICA Spitfire 1/5 Please Help

Spitty

What's important is that we keep the spirit of the men who flew these machines alive through our models. Modelers have a passion for their subjects and this passion is expressed on forums like this one. The internet allows us to freely communicate with each other and express opinions and pass on information. I'm raising my glass (full of course) and toasting you and all who use this device to keep the memories alive of the men who flew and often died in the machines we love to model. CHEERS!
Old 10-13-2004, 07:31 AM
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spitty
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Default RE: PICA Spitfire 1/5 Please Help

okay ,back to the thread.....
Again,I wondered about the really far forward located CG,checked it by 22.3 % , I checked other Spits like BT : 26.94 % and that should be okay( think, 25 - 28 % ) is a good choice for Spits.
In another thread , the guys wrote something about different CG´s ( old and new Pica Plans ) ???
So please : where is Your CG located????

Other Question : Everyone is dreaming of scale retracts and wheels... 5 inchs Wheels are a must for the Pica and I´m thinking about moving the Retract-Mount one inch forward ( to avoid noseovers ) by making a step into the Mainspars (okay,wouldn´t be that scale,but if it will makes takeoffs and landings more comfortable....)
Do You think this will be a problem for the structure ?
Thanks as always
Regards
Andy
Old 10-13-2004, 09:36 AM
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Moggy
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Default RE: PICA Spitfire 1/5 Please Help

CG is 4.5 inches from the leading edge dowel. The old plans had it at 3.5 inches but were amended to 4.5 inches.
Old 10-13-2004, 09:51 AM
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DaddySam
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Default RE: PICA Spitfire 1/5 Please Help

Andy
I made my retract mounts from a "U" shaped peice of aircraft ply (1/4" laminiated to make 1/2") and then did move the mounts forward and angled them forward too. They do look as if they point forward a bit much but then the nose over problem hasn't been a factor either. I fly off grass, and I guess if you fly off paved runways then it would not be as critical. The ply mounts take the place of the rails, and they do provide for reinforcement when you have to notch into the main spar. I also beefed up the spar. Sounds to me like you are right on track. I used 4" wheels and don't think it looks out of liine. Hope that helps.
Sam
Old 10-13-2004, 02:57 PM
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Ruudje
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Default RE: PICA Spitfire 1/5 Please Help

I also cut up the main spart to get the retracts more forward... In the next link, you can see how I did it...

http://www.rc-forum.nl/viewtopic.php...2d60076cb693a6

Hope you like it...
Old 10-14-2004, 08:58 AM
  #12  
spitty
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Default RE: PICA Spitfire 1/5 Please Help

Dag Ruudje,
thanks so much for the pics,will be very helpful,was searching Your site cause i had seen it months ago,but rcforum.NL wasn´t alive.
That made my day ( by the way,this year my Familie and I was twice in Holland ( Wemeldinge ,Sealand , near Middelburg ) next Year were are travelling again,love Your country!!!

Thanks also to Daddy Sam , but sorry,I can´t imagine what You mean with the " U " mounts .... Do You have pictures ???
Bye
Andy
Old 10-15-2004, 12:58 AM
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Ruudje
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Default RE: PICA Spitfire 1/5 Please Help

Your welcome,

if you need any more pics or onfo, let me know...
Old 10-15-2004, 02:01 AM
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DaddySam
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Default RE: PICA Spitfire 1/5 Please Help

I read about the "U" shaped mounts in Harry Higley's book "Mostly Mounting". Below is a sketch of what they look like. Basically, the mounts take the place of the gear mounting rails, and offer quite a bit of rigidity (if that's a word) to the ribs they are glued to.
Hope that helps. I could include a photo from the book, if that's not against some rule.
Sam
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Old 10-15-2004, 01:19 PM
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spitty
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Default RE: PICA Spitfire 1/5 Please Help

Oh Daddy Sam , I´m a Looser ( a bit stressed in the moment,I did that "U" for my little Spitfire....thanks for Posting the Picture) Thanks to all,so I will go with the longer PICA from Shindins ( just ordered via Tom) , put the gear 1 inch forward ( Thanks Ruudje ) and make the tail as light as possibe , ( also the Bulkheads after CG ) and try to do a perfect scalejob with all panel-lines,rivets and so on..(that makes the birds heavy)
Will use a SuperTigre 3250,maybe with a Krummscheid ( similar to Bisson ) or rear exhaust system
Will keep You advised ( by the way , how can I upload pictures.
Always happy landings
Andy
Old 10-23-2004, 02:30 AM
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genek
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Default RE: PICA Spitfire 1/5 Please Help

Hello guys. I read all of the posts w/ great interest. I just found a Pica 1/5 Spitfire at a yard sale. I do not have any plans for it or info on elevator throws or aileron throws. I see from your posts to set the CG at 4 1/2". I am thinking this plane needs a 20" prop, maybe 18"-8? Do you think a Q38 is ok for this plane? Can you give me the specs for the elv. and ail. ? Any info would be great. Gene
Old 10-25-2004, 10:39 PM
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Spitfire7856
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Default RE: PICA Spitfire 1/5 Please Help

Now you guys have me confused. Using the CG location indicated on the half size side view of the fuse shown on the plans, I calculate the CG to be six inches aft of the leading edge. Any thoughts would be appreciated. As it is now I will have to add 2.5 lbs to balance it there. If the CG is an inch and a half forward of that I am going to hang the plane and myself in the nearest English pub!
Regards
A3
Old 10-26-2004, 01:02 AM
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DaddySam
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Default RE: PICA Spitfire 1/5 Please Help

Spitfire 7856: The CG is 4.5 inches aft of the leading edge, right at the rear of former F-6. The older kits had the CG too far back and many crashed. I've read one of the original reviews in RC Modeler and this is what happened to the review plane. They built a second plane with a revised CG and it was fine. There is also another review in RC Report. The main complaint is the amount of lead needed to balance the plane. I had a G-62 in mine and still needed about 3 lbs of lead in the nose. If you have a light engine then 5 lbs of lead may not be far off. I also am using a Gene Barton spinner which has a soild 1/4" aluminum backplate, and STILL needed the lead. Now I'm putting in a 3w-50i and figure on up to four lbs. We'll see, should have an idea here sometime next month.

Gene: plans show elevator throw at 17 degrees up and down, Ailerons at 25 degrees up and down, and flaps 60 degrees. I'd have these as high rates to start with. My first two flights showed me the elevator is very sensitive, and when I get it airborne again I'll be more judicious about my control throws. Also, I have the plans and instruction manual (plans in front of me, manual somewhere) and would copy them and send them to you if you cover costs.
Hope that helps,
Sam
Old 10-26-2004, 01:32 AM
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Bish Wheeler
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Default RE: PICA Spitfire 1/5 Please Help

Spitty,

I built the PICA and scaled it out. It took a lot of work "up front" to make it scale, but it came out quite nice except the wing was just not right. Weight was 23 lbs with ST 3000 on ingnition with 5 lbs of lead. I crashed it on the first flight as the cg was goofy. I hated the wing (too thick at the tips among other things) so I pitched the wing and ordered a Yellow A/C wing kit. Beautiful even at the cost. Got the CG right, but taxiing was impossible as it nosed over every time. Ripped the retracts out and moved them an inch fwd (the heck with scale in this area) and now all is fine. If you have the CG in the right location you won't be able to taxi on anything but pavement and even then it will be "iffy".

Bish
Old 10-26-2004, 05:41 AM
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spitty
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Default RE: PICA Spitfire 1/5 Please Help

Thanks to All again,It´s amazing how much time and money You´ll save reading RC-Universe and get help of nice Guys.
With all the informations I´m on the right way.
When I start in the next few weeks, first thing I will do is replacing the bulkheads after CG.Then I will compute,how much deadweight I can save and keep You updated.

Bye
Andy
Old 10-26-2004, 07:52 AM
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Spitfire7856
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Default RE: PICA Spitfire 1/5 Please Help

Thanks for the great info. I have a First Place 3.2 with electronic ignition. To balance the plane at 4.5 inch aft of the leading edge I will probably have to add 4 lbs which will make the plane about 30 lbs empty. What are your thoughts.
Signed
Depressed in Florida

Regards
A3
Old 10-26-2004, 09:54 AM
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DaddySam
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Default RE: PICA Spitfire 1/5 Please Help

Don't be too depressed. The plane can handle it, and the engine choice is good. Make sure the mains are as far forward as you can get them. If you've already installed them, look at shimming the back of the retract plate to tilt the wheels forward. The reviews of the Spits with smaller engines (ST3000) talk about 'flying on the wing", which to me translates into careful power management. With the 3.2, I've heard nothing but positive things. I've also read in some reviews that once you get used to the plane you can remove some weight bit by bit. In the RCM review, I believe they were able to get back to about 3 lbs of lead after flying the plane for a bit. Chin up. That plane has a lot of wing area, and yours won't be the first 30lb Spit by a long shot.
Sam
Old 10-26-2004, 09:10 PM
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genek
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Default RE: PICA Spitfire 1/5 Please Help

Sam, thanks for the info on the Spitfire. I am going to finish this plane and then I'll see about starting one from a kit. Maybe. Thanks, Gene
Old 10-27-2004, 04:34 AM
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Red B.
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Default RE: PICA Spitfire 1/5 Please Help

If you can get the wight down to around 20 lbs the ST-3000 will fly the spit with authority.

The key to achieving the low weight is to keep everything aft of the wing as light as possible.
I replaced a most formers with balsa and carefully sanded the skin down to slightly more than half its original thickness before gluing it on the rear fuselage. The stab/elevators and the fin should also be put on a diet. Using closed loop wire linkage for elevators and rudder will also save a couple of ounces. Remember that every ounce in the tail equals approximately 5 oz. of lead in the nose!

IMHO an 18*8 is to little prop for an ST-3000. These engines need to be loaded down. An 18*10 prop will produce better results.
With the 18*8 there is to much RPM and not enough airspeed. Ideally the ST should be propped to approx. 7500 RPM on ground. It will unload a couple of hundred RPM. Remember, peak horsepower is deivered at only 8000 RPM.

Good luck with your Spit. It's a beaut!

/Red B.
Old 10-27-2004, 06:54 AM
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Spitfire7856
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Default RE: PICA Spitfire 1/5 Please Help

Thanks Sam for the encouraging words. You are right about 30# Spits- That's what my first one weighs. Was hoping to do better with #2!

Regards
A3

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