1/6 Pica Spit-Flying question  
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1/6 Pica Spit-Flying question - 6/6/2006 6:28:10 PM   
33LaKid


 

Posts: 52
Joined: 7/15/2005
From: Calhoun, LA, USA
Status: offline 		This may sound like a dumb question but I have a very nice 1/6 scale spit that I purchased and have put 6 flights on it thus far.
I am using this hopefully to hone my Spit flying skills as I build my 1/5 scale BT Spit. The spit weights 12 lbs.,I have checked the balance and it is balanced per the instructions and throws are per the instructions.
We have a nice grass runway and the spit flies great once it is airborn but takeoffs are iffy and landings-deadly.
The spit will not taxi at all without wanting to tip over(even with full up elevator). To take off, I have to employee someone to hold the tail down while I go to half throttle. Once it is released the tail will come up in about 10 feet or so and then I must come off the elevator (If I come off any sooner, it will nose over) I then go to full throttle while incorporating a small amount of right rudder. Once speed is obtained, it will lift off then the gear is sucked up.
Flying is like a pattern ship, it flies as if on rails...no complaints here.
Now for the problem...
Flap dropped to 30% on approach and throttle chopped,but no matter how smooth I set the mains on the grass as soon as the tail comes down, over she goes. Always leaving a bit of tweaking to follow before the next mission.

Any help from you pro's will be greatly appreciated.
Cheers,
Mickm

< Message edited by 33LaKid -- 6/6/2006 6:30:03 PM >
       Post #: 1

RE: 1/6 Pica Spit-Flying question - 6/6/2006 6:50:16 PM   
Red B.


 

Posts: 1034
Joined: 8/29/2002
From: Jonkoping, SWEDEN
Status: offline 		One could almost say that the nosing over tendencies is a Spitfire feature.
I have a 1/5 Pica Spit that has the same tendencies on long grass, the problem is not as severe as you describe but this is probably due to the bigger wheels on the 1/5 Spit compared to the 1/6. If the undercarriage is in the scale position, short grass and skillful use of elevator and throttle is a necessity.

What you can do to alleviate things a little bit is to mount washers under the rear gear mounts in order to tilt the undercarriage a little bit more forward. Have you checked the c.g.? If possible (check the instructions) you can try moving the c.g. back, every little bit helps.

/Red B.

_____________________________

/Red B.

(in reply to 33LaKid)
       Post #: 2

RE: 1/6 Pica Spit-Flying question - 6/6/2006 9:37:52 PM   
solarmusic


 

Posts: 0
Joined: 1/8/2003
From: St Petersburg , FL, USA
Status: offline 		Seems like a dumb question, but are you sure that it's a Pica? I have a 1/6 Pica and so does my flying buddy. These planes are around 8 - 9 pounds, not 14. There are no flaps on either. In any event the plan cg is 4 1/4 inches back from leading edge at fuse. Both of our planes are good flyers. We fly off asphalt, but occasionally land on the adjacent grass. If you don't haul back on elevator and gun the throttle a little once flying speed is eroded it will nose over. It happens to most warbirds. Small wheels don't help. Tipping the gear forward helps. And making sure that you have a lot of elevator. Learn to gun the throttle a couple of short bursts (about 1/4 ) with full up on the last part of the roll out, just at the point that you think it's going to tip over. Cut the grass real short and fill all the holes. Are you sure that's a Pica? Glenn

(in reply to Red B.)
       Post #: 3

RE: 1/6 Pica Spit-Flying question - 6/6/2006 10:36:16 PM   
33LaKid


 

Posts: 52
Joined: 7/15/2005
From: Calhoun, LA, USA
Status: offline 		I recieived the plans with it and they say "Pica". The plane is fully fiberglassed with a full cockpit and an OS-91 four stroke.
The wheels are in stock configuration and not as shown on the plans.If I cant them forward, would they still fit into the wheel wells properly? I have read where others have done this with good results and I may give it a look.
The wheels are smaller due to the 1/6 scale but the field is very smooth and the grass is cut short.
I haul back on the elevator as the tail starts to settle but it still tips over. I have not tried the short burst of throttle but will give it a try also.
I appreciate all input.
Cheers!
Mickm

(in reply to solarmusic)
       Post #: 4

RE: 1/6 Pica Spit-Flying question - 6/7/2006 12:46:51 AM   
scalebldr


 

Posts: 541
Joined: 11/8/2002
From: allenstown, NH, USA
Status: offline 		on conventional gear if the axles are not under or in front of the leading edge of the wing,nose over tendencies are the result wonde how much weight may have been added to the tail to balance the engine?

(in reply to 33LaKid)
       Post #: 5

RE: 1/6 Pica Spit-Flying question - 6/7/2006 2:37:26 AM   
33LaKid


 

Posts: 52
Joined: 7/15/2005
From: Calhoun, LA, USA
Status: offline 		Just getting home and want to say "thanks" for all the advice.
I just dug out the plans and they show the cg at 4 14" from where the wing meets the fuse.
I checked my plane and the cg is at 3 13/16". This could most diffently be an issue.
There is a large brass sleeve in the nose cone that I will remove and recheck.
As for the gear location, the wheels are slightly rearward of the leading edge. I will also look at trying to shim these froward a bit but the rails they are mounted to are at a pretty steep angle already.
Thanks again,
Cheers!
Mickm

(in reply to scalebldr)
       Post #: 6

RE: 1/6 Pica Spit-Flying question - 6/7/2006 5:41:31 AM   
ho2zoo



Posts: 712
Joined: 3/1/2002
From: Louisville, KY, USA
Status: online 		Sounds like mine. My Spit won't taxi more than a yard in the grass without nosing over. I modified mine to have flaps (helps greatly with the landings) and it has an OS .91 four-stroke. I'm not sure what it weighs but it's probably around 9 lbs. I fly off asphalt now but did fly a few times from grass. It required a very careful use of throttle and elevator (I don't know how I did it now).
But it flies so good that I don't dare change the balance. Landing on the hard surface I can usually keep it on it's feet. I know it's not much help, but I feel for ya...


_____________________________

It's like a Koala Bear crapped a rainbow in my brain!

(in reply to 33LaKid)
       Post #: 7

RE: 1/6 Pica Spit-Flying question - 6/7/2006 7:35:19 PM   
solarmusic


 

Posts: 0
Joined: 1/8/2003
From: St Petersburg , FL, USA
Status: offline 		Just had another thought. You may have to trim a sliver off the mounting rails to tilt the LG forward. Don't take it all off one rail. a hair off each is enough. A little off the forward one near the top and a little off the rear one near the bottom. You will be surprised at how much you can kant the gear housing without taking much off the mounting blocks. And, the wheels should still end up in the same place when retracted. I use the biggest foam wheels that will fit.Saves weight and stress on the retract servo. I got the ones with the checkerboard tread. They have about 100 landings on them and they're still good. Here's another thought. If you are using flaps, don't chop the throttle. You need to come in with some power on and fly it onto the ground. Maybe you are coming in too slow and as soon as the wheels feel the grass, they grab it because there is no forward thrust to create a roll out contacting the ground. Never land a warbird without a little power. I don't have flaps on mine and I am still able to land fairly slowly, always with a little power. Try some go arounds. Bring the plane in on final with throttle pulled back to maybe about 1/8th...let the plane loose some altitude...then as you get to where you think it is going to stop flying, add some throttle. I'm guessing at this point, I'm at about 8 or 10 feet. I add back in another 1/8th or more, so I am landing with about 1/4 throttle. The plane is still slowing down and losing altitude in a slightly nose up attitude, which is what you want. Once in groung effect, you begin to pull the nose up a tiny bit more. I don't think I ever chop the throttle untill I'm on the ground and rolling. At this point the grass is trying to pull the wheels back. The prop and elevator are preventing it from doing so. Truly, its a finess thing. If you are chopping the throttle, like a trainer, that could be your problem. CG is 4&1/4 and the weight should be about 9 LBS. Get all the heavy stuff out and move the servos forward. If you have to add weight, add it to the farthest point on the engine mounting rails, not the spinner or firewall. Glenn

(in reply to ho2zoo)
       Post #: 8

RE: 1/6 Pica Spit-Flying question - 6/8/2006 5:04:24 AM   
33LaKid


 

Posts: 52
Joined: 7/15/2005
From: Calhoun, LA, USA
Status: offline 		Thanks for the pointers Glenn, however I am comming in quite hot. I would love to come in a bit slower but due to some trees in the vacinity, I must be sure I am clear of them prior to decent. I am pickup up speed as I come down my final approach.
I have flown many warbirds but never owned a Spit before. I am starting to understand why. I love the line and overall flight charistics of the Spit but landing is a bear.
I am going to rebalance and try again.
Cheers!
Mickm

(in reply to solarmusic)
       Post #: 9

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