ACROHUNTER

I'm building the 1/7 scale P-51 from Top Flite .60 - .91, and don't want to run on Pneumatic Retracts, basically because of the complications and price.
Does anyone know who servo retract will fit on this model?.

Thanks for the help.

Richard L.

My Feedback: (24)

You are asking for trouble if you don't use pneumatic retracts on this plane. What's so complicated about pneumatic retracts? They are much easier to deal with than mechanical retracts. Since you plan to go with mechanicals, any retract servo would work since all retract servos are roughly the same size. You will need two, one for each gear unless you plan to use light wire struts and light wheels. Keep in mind that mechanical retracts for plane this heavy will be flimsy. Take a look at the H9 Mustang for example. That plane only weighs 8.5 lbs, which is much less than your TF P-51. However, the supplied mechanical retracts for the H9 P-51 are marginal.

parabellum

yes, cost is a big concern.

complication may not be a real concern though.

if you want simplicity, try springair retract.

you only need one tubing to each retract, unlike most of the other makers.

may or may not be a good thing, but can't deny it's simple.

http://www.retracts.com

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btw, angle your retract, so that the pivot is a bit infront of the wheels when retracted. and wheels should be infront of the pivot point when extended.

that's how it really is in the real thing, and will require 90 degree retract.


if you set retract perpendicular to the fuselage, as most models and plans
suggest, you will need 85 degree retract.

abufletcher

Retractable gear seems like a pain in the neck and the weak link in the chain from what I've seen out at the field. I've seen planes with one gear down or no gear. I just can't see paying $250+ (more than the cost of most kits) for retracts that sometimes work. I think I'll just stick with WWI birds or maybe a Stuka!

rc34074

My Feedback: (5)

i recommend the Spring Air 116 retracts. these are air operated and are fairly simple to set up - Spring Air gives you a plumbing diagram. they use a standard servo. you can use the wires that come with the kit with these- Top Flite gives you a good music wire strut, so all you do is cut them to the right length to fit into the retract.

also- no matter what retracts you get be sure to beef up the wing ribs. a rough landing will knock the gear mounts out of the wing. top flite's gear mounts are notoriously weak- there have even been articles about how to do this in magazines!! i would just make a duplicate set of plywood doublers and put them on the other side of the ribs i addition to the original set.

ed

DavidAgar

My Feedback: (108)

The up side to Spring Air is they will come down and lock in the event of air pressure loss. They are spring loaded down. I would highly recommend getting the 3/16 inch struts as the 5/32 tend to bend in the event of a less than perfect landing. As mentioned they are easy to set up and plumb. Good Luck, Dave

eugene

acrohunter....Get a set of Spring-Air's.. with the 3/8 trunion block, and a 3/8 oleo strut. super simple to install, never fail to extend, and very durable...Have a set on my TF P-51.. the servos, wires , set up, adjusting the mechanicals, and straightening the leg wires after every day of flying will soon grow old...

donalddresser

My Feedback: (3)

I agree totaly with Eugene, get the set bored for Oleo's. I have a set in my Top Flite Fw 190 and they are great. Also you are going to spend a ton of money on building the thing spend the extra money to get the right set of retracts that you will be happy with. I fly off a grass field and I have never had a prblem with the retracts binding or not standing up to the abuse of the grass. I also have a few set that use the strait wire, and they are a pain in the neck. The wire will bend if the landing is not perfect, then you have to bend the things back into position. The retracts with the wire are find for a sport scale like a great planes p-51, but will suck on your heavier Top Flite kit.

Skeletor

Ditto on the Spring Air and beefing up the mounts and ribs.

rc34074

My Feedback: (5)

i would strongly recommend against the 600 series robarts. i recommended the top flite p51 wires because i have used them and i know the ones i have are made from good strong 3/16 music wire which does not bend easily. some arfs come with soft wire struts and those soft wires are a real pain. if you want oleos go for 7/16 oleos - with robart 500 series retracts.

ed

eugene

The 3/8 and the 1/2 " robart oleos will also fit in the Spring Air trunion block of that size...

Richard L.

My Feedback: (24)

I have Robart 551RS retracts and 7/16" diameter oleo struts on mine:

eugene

very neat looking wing, clean workmanship

donalddresser

My Feedback: (3)

The reason I do not like Robart is because they use a music wire that goes down into the Oleo Strut. This wire is prone to twist on landing due to being held in place by a set screw. The Spring Air Oleo retracts have a socket that you put the Oleo strut in and then you tighten the socket, they will not twist. Spring air also uses a nice heavy gage Aluminum for the frame of the retract, and lastly if you loose air pressure the retract comes down and locks. The Robarts come down but they are not locked so you will be sliding your nice plane on it's belly down the runway. If you want a good source for nice struts call Ray Litefoot at
FN:Ray Litefoot
N:Litefoot;Ray;;Mr.;
ADR;WORK:;;138 Emerald Rd;Seneca;SC;29678;
TEL;WORK:864 886-0095
EMAIL;WORK;PREF;INTERNET:[email protected]
TITLE:Owner
ORG:Liteflite
NOTE:Owner of Liteflite strutts for rc airplanes.

He makes a very nice Oleo strut, he makes them out of Aluminum so they are much lighter than the Robo Strut. Anyway go check out the Spring Air Website, best of luck on your project.

Richard L.

My Feedback: (24)

Robart 551RS in my picture above do not use a music wire. The 530 and 550 series are bored out for 3/8" and 7/16" diameter oleo struts. These oleo struts are inserted directly into the retract mechanisms without the need for music wire or set screw.

DMehalko

My Feedback: (42)

I aggree with just about all the replies here.

You will not be happy with mechanical retracts on this bird, why spend all the time and building and not go the extra ten yards? Retract servos will also only help drain your rx pack, and for price of these things is really not that bad. I just picked up a set of CJM pneumatic rectracts for my sea fury at only $175