Help with my first built-up model - RC Groups
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Mar 17, 2004, 09:52 PM
Registered User

Help with my first built-up model

H'loo Everyone,

I'm just finished putting the frame together for my first built-up model; a peanut scale SIG kit. I've done a number of kits for C/L, but this is my first FF. The instructions are a bit unclear and I thought I'd ask:

1) I have a dowel around which the rubber-band should be run; do I install it permanently, or should I allow it to penetrate the sides of the craft (and be removable) to make installing the rubber-band easier?

2) how do I go about installing the rubber-band, or a new one, if the band snaps once the paper covering is in place?

3) folded double, the band is about 2 inches longer than the space inside the fuselage. Should I shorten it to keep the nose block attached with tension? I'm afraid the nose block will fall off at the end of the flight.

Thanks for your help!
Solomon Gerdawr
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Mar 18, 2004, 09:32 PM
Registered User
TLyttle's Avatar
Which model is it?

By all means have the dowel removeable; replacing the motor will otherwise be VERY time-consuming, and trust me, you will be replacing the motor for various reasons. Not enough power, too much power, rubber "wears out", on and on. Have an opening in the covering (usually on the bottom) near the peg so that you can see what you are doing.

Make sure the noseblock is a tight fit and stays in place when there is no tension on the motor. Use a length of wire to fish the loop through, and to fish out any pieces of a blown motor. Do not shorten the motor, it sounds about right (I won't get into "braiding" a motor to shorten it, but it can be done particularly on motors up to twicethe fuse length!).

Most importantly, LUBE THE MOTOR! I have been using green soap and glycerine (get it from the drug store) for 50 years now. There are other products on the market, but none cheaper. Buy the smallest quantities of each, mix 'em together, they should last you a lifetime. Dip the end of the rubber into the mix, and rub the motor between your hands until all the rubber is covered. TIE THE KNOT BEFORE you do this, otherwise the knot will never hold. Use an overhand knot to tie it, followed by a square knot; never fails, use water or saliva to dampen the ends of the rubber before you tie it.

Use a winder (even a cordless drill works!) and stretch the motor to twice its length and wind a couple of hundred turns, working up from there with each flight. If you want to find out how much it will take, wind another similar motor outside the model until it blows, then reduce that number ~20%. I never wind to 100%, not for any reason.

That should get you started!
Mar 19, 2004, 10:07 AM
Registered User
Thanks; I'll try your suggestions.

Whoops; It wasn't a SIG after all; it's a Microx Stinson 125. The kit went together easily enough, although the nose-block doesn't fit tightly at all. (Probably a 1/8" gap on either side, but I could add scrap to make it fit.)

I assume I need to cover the fuse, wing and tail surfaces before attaching them together. On a peanut scale I assume that gluing the wing on is S.O.P. where on the C/L's I've done the wing was held on by rubber-bands.

Green soap; do you mean a dish-washing detergent or simple green, or is there something called "Green Soap?"

Thanks again for the help!
Mar 19, 2004, 08:59 PM
Registered User
TLyttle's Avatar
Hmm, Micro X, nice kits from what I remember, should be a good flier. By all means, shim the noseblock for a tight fit, It should require some effort (or as much as a built-up model will easily stand) to remove it.

Yup, cover everything before assembly, and glue all parts. On some models, you can get away with rubber cement, but that is usually on larger ones, don't try that yet.

Green soap. Ask for it at the pharmacy/drug store, they will show it to you. It is usually used for applications where cost is a consideration, and it used to be the soap of choice in public facilities. I understand it is also for people with skin allergies, so this stuff won't hurt anything... including rubber.

Have fun! This is the most challenging facet of the hobby as far as I am concerned: I have handed peanut kits to 1/4 scalers, and none of them has ever gotten 30sec out of a peanut! Once you master rubber models, all else is easy.
Mar 23, 2004, 11:49 PM
Indoor Free Flight Modeler
'Son of A Gun' is an excellent rubber lubricant as is any silicone oil. If you buy Son of a gun you can use it straight up or pour it into a big bowl and let is sit out a few days to let the water evaporate out of it and you will be left with a thicker fluid which is excellent to use.
Mar 24, 2004, 10:16 AM
Registered User
Do either of these products ('Son of A Gun' or Green Soap + Glycerine) leave traces or lines on the paper from the installation of the rubber band in the fuselage?

Also, is there an easier way of dropping the band down to the rear dowel? (Right now I'm using a pliers to grab it and hold it in place while I shove the bar through the loop.)

Thanks much!
Mar 24, 2004, 09:26 PM
Registered User
TLyttle's Avatar
Any lube will leave marks if you use too much, I dip the last inch or so into the solution and rub it between my hands until there is no actual liquid left. I assume that SoG will react about the same; if you use too much just add a small rag with the rubber and keep going.

As far as getting the motor in there is concerned, I always leave an open patch below the motor peg, and install in one of two ways: either cut a notch into the end of a length of ~1/8 square, loop the motor over it, and install. with the open area, you will easily see to inistall the peg. Other way is to take a piece of wire, bend a hook into one end, fish it through the opening below the peg, hang rubber on the hook pull it through. Your choice, but I suggest the wire because you will doubtlessly need it to remove blown motors later!
Apr 14, 2004, 06:07 PM
Go get them Meg!
lrsudog's Avatar
There are also commercially available "Rubber lube" products on the market specifically designed for free flight rubber motors. Glycerine also works. The trick is to massage it into the rubber, except where you tie the ends together if you are using strip rubber. No lube on the knot. Then wipe as much of as you can with your bare hands.

For installing the loops of rubber, I always used a wooden dowel with two notches cut into the end. One notch is just to hold the looped end of the rubber and the other notch is big & deep enough for the peg to slide through.
Apr 30, 2004, 02:56 AM
Registered User
Hello everyone. Wow, I didn't realize so many people still flew rubber-powered planes. I fly electric R/C and lately have been toying with rubber power. I've built a couple of simple balsa planes with food-wrap covering powered with normal rubber bands *gasp* It would go up about 50', then the motor would finish its winds and since I have no idea what I am doing, I don't know how to make some sort of freewheeling device. So, it would come straight down from the drag of my heavy plastic 7" prop.

Hehee, what fun a 14 year-old can have with a rubber band.

Anyways I found this awesome site that has plans from MAN for hundreds of scale rubber powered planes. (I'll go back and find it) I am quite proficient with balsa and know I could make one pretty light, but I have no idea where to get the rubber, props, freewheeling device, tissue, dope (whatever that is? Some type of water-based glue?), winder (or, yes, I could use a drill) etc. Any suggestions?

Or will you all suggest I get a starter kit ARF? Fine with me- just point me where.

Apr 30, 2004, 03:01 AM
Registered User
dslusarc- Nice webpage too!

May 02, 2004, 04:51 PM
Registered User
There is a book "Rubber Powered Model Airplanes" by Don Ross.
It will answer ALL your questions. Around $15.00. Hobby Shops usualy carry it.
May 03, 2004, 03:56 AM
Registered User
Chris, if you have a look at the "Free Flight Resources" thread at the top of the forum you should be able to get plenty of useful ideas. I know several good suppliers here in the UK but I guess you need somewhat more local vendors .

Good luck - Steve
May 04, 2004, 10:55 PM
Registered User
Or will you all suggest I get a starter kit ARF? Fine with me- just point me where.


Hi Chris,
I can point you to a hobby shop that carries alot of great RBFF kits.
the name of it is Penn Valley Hobby Shop and it can be found here:

They've got alot in the way of Rubber powered FF and also carry the products that the previous gentlemen mentioned.

FWIW, I think that Rubber Powered FF is alive and well and many modelers find it very challenging...even some that have been flying C/L or R/C for years!

Good luck.
May 05, 2004, 09:22 PM
Registered User
TLyttle's Avatar
Man, that's a fact! I have spent many years showing hotshot r/c guys just how difficult f/f rubber is, particularly scale, specifically Peanut; whole new attitude after some exposure.

As far as ARF is concerned, there was a kid in our group that used to buy a Sleek Streek (they still available?) every friday, fly it indoors that evening, take it outdoors saturday and fly it until it flew away in a passing thermal! He would sand the wings & tail, thin down the fuse, change the rubber, and borrow my winder. Once he got the formula right, those models never made it to Sunday in his hands.

Fun is where you find it...
May 05, 2004, 09:37 PM
Registered User
Yes, the Sleek Streak is still available. And for a mere 1.99. I cannot find it now but I once found a website that offered great mods. I did this and the thing flew away! One of the mods I can recall was to replace the motor stick with a longer motor stick (about 4" longer) and use good rubber. I had a blast flying it and even inspired my Brother in law to buy one.

About the peanuts. I love to build'em, just can't seem to fly'em well. I had my best success with a Peck's Mustang. I'm currently scratch building a Mauboussin Hempitere. Well sort of, it's on the back burner as I'm building a dimer Spitfire. But peanuts are a real treat.

Have fun,