Mountin' Profile tanks

Guy's I am lookin' for a neeter way to mount the tank on a profile, other than hooks and rubber bands.
I'll be usin' plastic tanks (clunk) so any help will be greatfully appreciated..

>
> Guy's I am lookin' for a neeter way to mount the tank on a
>profile, other than hooks and rubber bands.
> I'll be usin' plastic tanks (clunk) so any help will be
>greatfully appreciated..

I never liked rubber bands either. When I build a profile I cut a hole in the plywood doubler the same size as the fuel tank. I insert the tank into the hole. I always make my fuel tanks a little larger than they need to be that way I can put any amount of fuel in there that I want, 8 minutes, 10 min, 15 min. I put 5 min epoxy glue on the fuel tank and push it into the hole in the profile fuselage. 5/8" of the fuel tank is inside the fuselage and the other 5/8" is sticking out. The advantage of a clunk tank over a wedge tank is I can put 1 minute of fuel in the tank to do a short test flight a wedge tank has to be a little more than half full of fuel the get the engine started. With a plastic fuel tank I would make 2 metal straps around the outer half of the tank. I would screw each end of the strap to the plywood double with some tiny screws.

This was essentially the method used by Bill Hopkins on the Custom Models' designs (Forerunner, Profile Nobler, etc.) On these designs the tank was mounted inboard, but we reversed it and put it back outboard.

Although these seemed to work fine that way, it did not allow for much adjustment in height, and did weaken the nose somewhat. I like to have a stiff nose with full motor mounts going all the way back to the wing.

Everything is a compromise.

>
> Guy's I am lookin' for a neeter way to mount the tank on a
>profile, other than hooks and rubber bands.
> I'll be usin' plastic tanks (clunk) so any help will be
>greatfully appreciated..

Actually plastic tanks are easy. You can put a couple of long screws through the middle of these a whole lot easier than you can with those metal wedge tanks.

(Sorry, I couldn't resist it.)

Rubber bands may still be your best bet here. We made a plywood cradle that fit under the tank (between the tank and the fuselage) and was held on with two screws with vertical slots allowing the cradle to be moved up or down. You need to remove the tank from the cradle to adjust, but It is still concealed when the tank is back on. Once the tank is adjusted properly, you don't need to keep messing with this anyway. And some will even move the uniflow tube inside which I don't really agree with. It "sort of" works, but the best bet is to leave the uniflow in the middle and adjust the tank height.

I got so frustrated with plastic tanks, however--always something going wrong with it--that I went back to metal. But on the profile, I used the same approach on the metal tank, although with these you can also solder the tabs to the front and back or top and bottom for mounting.

LAST EDITED ON Dec-11-04 AT 10:19 AM (CST)
 
If you don't like rubber bands, cut a piece of neoprene tubing and form it into a circle by sticking a piece of 4/40 screw or 1/8 in. tubing in the ends. Cut to the right length it acts like one BIG rubber band and will hold the tank securely and neatly. Neoprene is tough and resistant to sun and fuel. Holds up forever, compared to rubber bands. Plus it's easy to wash off.

The hook mounts are fairly easy too. I added them while reparing the plane after a straight in crash. Drill into the fuse for 1/4 in. dowel. Epoxy or polyurethane in place. Center drill 1/16 in. Make up some hooks out of 1/16 in. music wire. Rough up the end that will go into the fuse with a side cutters. CA in place.

I have held tanks in using tyewraps - the plastic cable ties

Regards

Mike

I make my hooks from piano wire, notched near the straight end for a mechanical fit with my epoxy adhesive. After finishing the fuselage, I drill holes of the same diameter, clean the wires with acetone, and epoxy the wires in place with the notches submerged in the holes. I let the epoxy soak into the wood before inserting my hooks. A small bit of epoxy is then pushed to the surface and mostly removed with a paper towel corner. So far there seems to be no seepage of raw fuel along the sealed interfaces.

SK

This my style. It has worked well many times, NO problems.

I cut a hole in the fuselage and mount the tank on the CENTERLINE, where it wants to be. Inboard is bad, outboard is bad. On center is a good thing.

Glue in the tank with silicone bath tub sealer, like the pan-rats of old. I start out with the tank 1/8" above CL of venturi. If it doesn't work, cut it out with a hot X-Acto knife and try again. Things that are too easy to adjust add weight and fall apart.

I dunno Gil, Wire hooks and rubberbands are good enough for me.

Ko,

What's the plane, Paul? Some sort of Spit profile? Looks quite interesting . . .

I know a guy that uses one 1/4-20 nylon bolt to hold the tank on. You have to have a piece of tubing going crossways through the tank. For a plastic tank I guess you could try gluing the tube in with JB weld.

Why use a plastic tank?

If I ever get a round tuit, I use 2 or 3 dabs of RTV on the inboard side of recessed tanks on my profiles, once the proper height has been established with plywood shims. However, I tend to NOT do that, and use rubber bands forever. Even as they melt and fail.

On one occasion, I finally added the 3 dabs of RTV, and IMMEDIATELY the tank developed a leak, so I had to remove it. You wouldn't think that RTV would stick that well, would you? But I ended up using my big channel lock pliars to grab the tank and twisted it out like the dentist pulling one of my wisdom teeth.. (Prior to gluing it in, it had not leaked, of course)!

I found what I thought were some nice long rubber bands at the grocery store on bunches of broccoli. I used them for about 2 flights, before the fuel attacked them and released the tank - where else? In the inverted pullout of the reverse wingover! The tank swung out on its fuel line, slammed into the wooden prop and broke one end off, and killed the engine - I "landed" upside down..

[photo not recovered: 3e69bb3870f12ad5.jpg]

"I am not a vegetarian because I love animals; I am a vegetarian because I hate plants." -A. Whitney Brown

Guy's,
I do 'ppreciate the answers, as usual ALL the info can be found on this forum...
Thanks again;)

Will try to get some pictures and add them to this post. Basic technique is as follows:
1) Get a piece of lite ply about the same height as the plastic tank you're using. Length should allow 3/8" more forward and aft of the tank.
2) Cut out the center of the lite-ply....about 1/8 to 3/16 inches smaller than the outline of the tank.
3) Bevel the edges of the inside of the cutout so the tank rests in the cradle formed by the bevel.
4) Glue additional pieces of lite ply on the back...but leave two 1/4 inch gaps running vertical...position the gaps so you can rest the tank in the cradle and secure with nylon tie wraps running through the notches.
5) Trim away any of the lite ply from the inside and outside coutour of the original frame. Drill and slot holes for mounting to the fuselage. Slots allow for verticle adjustment.
6) Sand and finish to match your plane.
7) Secure the tank to the finished frame with nylon tie wraps.
8) Mount the frame to the fuselage. Loosening mount screws will allow the entire frame/tank to slide up or down as needed.
9) No rubber-bands to wear out and break.

Using this setup on my Brodak Zero....but switched from plastic to metal uniflow. Works very well!

Good luck! Hope I follow up with pictures as an edit to this post.

I borrowed this idea from someone here on ssw. Works for me.

Thanks
Paul

That's close and will work! Only effective difference is using nylon cable ties in place of the music wire and rubber bands. The rubber bands need frequent replacement.

Gil, I got this from Dale McCord in Dallas, I should of shown you when I was at the Rouge. Cut a piece of 3/32" Ply a 1/4" bigger, top and bottom and 1/2" longer (fore and aft) than the side of the tank you want against the fuselage. Scuff (sand paper)and clean that side of the tank REAL good with solvent. Apply a single strip (3/4"wide) of the 3-M soft 3/32" thick double stick tape down the centerline of the scuffed side of the tank. Liberally apply an even coat (1/8" thick) of Dow Corning or GE RTV Silicone (Silastic) to the exposed, scuffed areas and press it on to the ply, squared up, until the tape sticks and the RTV extrudes out. Using a tongue depressor remove the excess RTV, however, leaving a radius fillet. You can mix up a little dish soap and water, dip your finger and smooth out the RTV. Let it cure for a day or so. Cut your vertical slots in the fore and aft ends of the ply, coat the exposed ply with five minute epoxie(thin coat)let dry, install on the fuselage and adjust. This process has been on my modified Twister all this season and is still going strong. Not only reliable, but light. As soon as I get done grading papers...I'll post a picture. Norm BTW This is for a plastic clunk.

LAST EDITED ON Dec-14-04 AT 09:02 PM (CST)
 
Gil, here are those pics I promised in my last post of how I did my Clunk Tank.

"Hey Norm", thanks for the publicity! I just about had my patent form ready to send in for the tank mount, now you sent the idea to the world! " Just kidding!" See ya in Houston. Merry Christmas. DRM

Wow! Patent?...never gave that a thought. Your tank installation is very practical and light...inspired me to share it with all..."Kudos."
I thought Dallas was first? Presidents Day?

Nylon cable ties work well for quick and simple installations. They don't require any hooks and don't rot like rubber bands. You can buy a big plastic container of assorted sizes for $10 at the Home Depot. You'll find *many* uses for them!

Andy

I really think you guys are wasting a lot of time with "Doo-dads for Stupid Profiles" when screwing around, trying to make mounting a tank into some sort of art form.

Tanks on profiles ought be simple, reliable and easy to adjust up or down. That means some sort of hooks, and I described my choice in a recent issue of Stunt News. Double-sided tape to hold it in place. Band of silicone tubing, as just tape isn't good enough.

Of course it's ugly! But does anyone know how to make a really pretty profile model? C'mon...

Being relatively new to SSW and being an avid reader...It didn't take long to figure out where it "got stirred."

"The witch is stirrin' the POO"........
Circlepilot u'r my kinda guy.... Gil;-)

Dan,
“Stupid Profiles” are all I know how to build. I do not have the money or the skill to build stuff like Sparky.
I would hate to think that I am waisting my time on Stupid Profiles with a lot of other people here on SSW.
I would take offence to your remarks if it were anyone else and these would be fighting words. (I have seen your hard point handle)=)
But I don’t take myself to serious with my toy planes and I have learned not to take you serious either.
But other new comers here might be offended.

My son posted pictures of his new “Stupid Profile” Buster, and got a lot of nice replys. I am very greatful to those to take the time to encourge my two boys in this hobby.
I know deep down you are a real nice person, just sometime your brain is not engaged when you get to the keyboard.

God loves you and I am working on it.
Merry Christmas!

Paul

LAST EDITED ON Dec-16-04 AT 07:33 PM (CST)
 
I went to the Home Depot and bought some Indutrial strength "Velcro" to attach a power strip to the side of my work bench.

I had some left over and cut a patch the same size as my fuel tank on my Flight Streak. This stuff has a grey epoxy glue on each side and is peel and stick.

It hasn't fallen off yet! (smiles) Apparently there are different grades of this stuff. It takes three men and a boy to pull this stuff appart.

It's a nice clean adjustable install.

I kinda like Leonards way of mounting tanks, Drill a hole all the way through the tank and the fuse and run a bolt through it.

Regards,
John Jolley

edit, never could spell....

Dan, this sport is " an art form ". Just like someone who paints on canvas, and hangs their work on a wall, there are different levels of expertise. We all can not be "expert" flyers, or builders. But most of us take pride in what we build, and fly. You know, I do not see many (maybe none) beginner , intermediate, or even advanced flyers slamming the "expert" class. ( I only assume that is where you are ). I finished second this past year for the Distict 8 Trophy, behind Mr. D. Gleason, ahead of some very good flyers from Dallas, Houston, etc., flying a lowly " profile ". ( by the way, thanks Gordon for designing the Pathfinder ). I disagree that you can not build a pretty profile. I guess what matters is who is looking at it. From " one side " only, DRM.

Good Grief, Profiles are all Dan writes about in Stunt News. Did you really think he was serious? How long have you guys been reading his Blab.....

John

>Good Grief, Profiles are all Dan writes about in Stunt News.
>Did you really think he was serious? How long have you guys
>been reading his Blab.....
>
>John

Cripes, John can't be the only one to get it! In 2004 I spent far more time flying profiles--both in practice and in contests--than full-fuselage models, thanks to losing my Oriental at second contest of the year, the expansion of P-40 in this area, the basic goodness of the particular profiles I am flying.

The point was that we simply cannot take advantage of the inherent simple nature of profiles by throwing trick (read: time consuming) stuff at them.

Look, go back to the second of two (voluminous) Bad Boy Stunt articles from 2004 Stunt News dealing with a very specific small-bore engine and CL profile models. Other than the Q-ship ARF Flite Streak, a.k.a. the "Dirtmobile," which was--and is--intentionally a whack job as to appearance, you can see neat, clean and functional tank mounting on a couple of my profile models. Emphasis on *functional,* as you simply cannot create a beautiful profile model with that ugly tank hanging off to the side, I don't care how much time you invest in the folly of it.

Some of you guys are really going to have to learn to place comments made here in some sort of context.

Thanks, John!

! Got ya ! I love this forum, and this sport.DRM