Arrow Build

[ADW 123]

im building the 700 series Arrow... i was wondering if i could have any tips on how to make one of these 700 series a rubber powered model.... Any suggestions? i already have all frames build, the wind covered (except for the tips) and stabilizer and rudder covered. just need to know how to get it to fly... ive really never build for rubber powered i usually build for show....

[krob]

Check this site out http://www.gryffinaero.com/models/ffpages/tips/10step.html

I'm learning to fly these too and it seems all trimming processes are roughly the same. I found this site to be the most straight forward. Besides that I'd say take your time and go back some steps if you need to. I had tried a scale rubber model before and just built it, wound it up and tossed it. Obviously didn't work. This time I'm being slow and methodic and my plane is flying. Oh ya, if you haven't allready, read through these forums. I finally had a clud after I did.

[ADW 123]

ok but what about how to set up the rubber band.... someone told me that i had to lubricate it and make the rubber band 1.5 times long but with this 700 series, the rubber band would get tangled up inside the fuselage, so do i make the rubber band so it fits the prop hook to rear motor mount length?

[krob]

Well this is were I'm learning right along side you. But even in my limited experience, I know the kit rubber is crap. You don't have to do the 1.5x hook to peg length. That's just if you want maximum efficiency. The sagging you're talking about; I wouldn't worry about that. I imagine by the time the motor is sagging it's not producing much power any more. For thickness of rubber, I'm still trying to figure this out. I've got some different thickness of tan on order, and I'm going to try different combos. Besides that, hopefully your thrust bearing is held snug some how, so you can make thrust adjustments and when your motor runs out the whole mess doesn't fall out the nose. See if you can get a hold of Don Ross's "Rubber Powered Model Airplanes". Lots of good info for newbies like us.

[ADW 123]

maybe i should try the rubber inside the kit... im going to lubricate it with some type of oil too

[krob]

I use Armorall with silicone. Not sure if this is good or not, it's just what I had. If you use kit rubber, be conservative on winds. If it snaps, it'll probably do damage. Better yet figure out how many winds you're going to shoot for, and try winding it up that much outside the plane to see if it can take it. Let me know how it goes.

[ADW 123]

all i want is to achieve flight for my first time and that means only 10-20 seconds from launch to land

[CaliforniaDan]

Using the kit rubber you will probably get only 10-20 seconds of flight time. I have tried longer pieces of rubber in my models, usually twice the length of the normal distance between the front to back hook and have gotten some decent flying. What I have done is double looped the rubber back on itself so it will still fit in the model. I usually wind up to 300-400.

The thickness or width of the rubber loop will depend on the size of your model. If it is to small your model will just putter, if it is too big like I did in one of my models, it might zoom up quickly and do a barrel roll before it putters out. The Flying Model Book is good reference that will give you a guide as to what thickness you should use based on the wingspan of your model. If you can't get a hold of the book let me know and I can look up the info and post it here.

[ADW 123]

10 to 20 seconds is what i want for now... i lubricated my rubber band with 4 cycle oil (non synthedic) is what people told me to use to lube the rubber, and i am now working on finishing the covering on my plane... i should be able to balance and test glide my model in only a couple of days. should i put the landing gear in my plane because ive always had problems with the stupid landing gear breaking when it lands so what i am going to do is not even put in the landing gear to make it easier but what im woried about is the propeller hittingthe gound when it lands and possably bending/breaking. on the link that krob sent me it says that i should test glide without the prop... is that right?

[kittyfritters]

Do not use anything with mineral oil in it to lubricate rubber. The rubber will deteriorate very quickly. The classic rubber lube is green soap and glycerin. This is messy and gets all over the inside of the model. Currently the automotive silicone sprays are your best bet. They dry, but lube while dry so the inside of the model stays clean. Put the tied rubber motor in a sandwich bag, spray the silicone inside, and rub it around in the bag to get it thoroughly coated, then install the motor.

The Arrow is a little tight inside, but if built straight is a good flier. The trick with motors longer than the hook to peg length is to keep the nose block on tight. In fact, the big trick to trimming rubber powered models, period, is to keep the nose block on tight. That way any adjustments you make to the thrust line have authority. Nose block design has been a weak point in Guillow's models. There are a number of ways to keep a removable nose block on tight, but I currently favor using small rare earth magnets (Available at Michael's and other craft stores.) embedded in the first former and the back of the nose block to hold the nose block on.

There is a chart of maximum allowable rubber winds on page 91 of Don Ross' classic "Rubber Powered Model Airplanes". The chart seems to work for F.A.I. tan, sport rubber. With four strands of 1/8 inch flat in a 20 inch motor for your Arrow you could get 1380 turns, max, and would probably normally fly with 1100 turns. On a warm day you would stand a good chance of loosing it without a dethermalizer.

[ADW 123]

im only shooting for a 10-20 second flight, and i used oil on it and the rubber seems ok, but if it breaks, then i will pull out the rubber and take of the prop and use it as a glider that i can throw, then buy a new one and try again... but am i right not installing the landing gear? also, where do i get a removeable noseblock?

[kittyfritters]

You have to make a removable nose block. Takes a little re-engineering.of the front end of the model.

The simplest way with the Arrow is to cut another front former, as a disk, with a hole in it for the thrust button, Cut a square hole in the front former on the fuselage and cut the identical sized square of wood that is at least twice as thick as the front former and glue it to the center of the back of the disk, which is not the removable nose block, as a key to keep it in place. Now, with the new removable nose block you can easily install rubber motors through the new, larger, square hole in the front of the fuselage and you can put balsa pieces on the front former to wedge the removable nose block up or down, right or left, to adjust the trim of the thrust line.

I like to face my front former and back of a removable nose block with 1/64 inch plywood to minimize wear, but I have models that I have been flying for six years.

[kittyfritters]

OOPS! I wish this board had the edit feature. That should have said, "which is now the removable nose block".