I have this old Kwik Fli III, and am debating how to power it. I have an old OS .60 "Max" blackhead engine with the "strap on" muffler, which would look very authentic, but that probably doesn't even have as much power as a new .46 I'm guessing. I also have an OS .91 FX with a tuned pipe. This would make the finished plane weigh about 7 lbs. Would be a good combination? I'm looking for unlimited vertical here.

tooooo much!!

I’m a power junky too! My Kwik Fli III taper wing is pretty fast with the gear retracted and it is only powered with an Irvine 61 ABC. With a pipe it would be unlimited vertical. The taper wing would be faster than the standard wing.

The smallest prop that OS recommends for the 91 FX is 13�, so expect you would have prop clearance problems. You might see if you could find an OS 61 SF ABC-P and put a pipe on it. They put out incredible power and use a 12 -10 APC prop.

Way tooooo much!

Maybe you should change your username to Tommybullet.

I would follow 8178's advice on this one. If you do decide to use the .91, be sure to do some throttle management, specially on dives, as that setup has "flutter" written all over it. Worst case scenario, you could see the airframe fail right before your eyes (less likely). I'm assuming that the Kwik was built a long time ago and stored, and that you're dusting it off.

If what you mean is that you have an old kit that you're going to build, then think of the extra stress the .91 is going to put the airframe through and reinforce it accordingly.

Good luck.

Tommy,

Considering that I really like the Ballistic Pattern planes, I would go with the .91 with pipe. You will have to make certain you have zero slop control surfaces with no hinge gap or your plane will be ballistic in more than speed. Flutter is a very real problem with Ballistic Pattern Ships and all it takes is careful rigging and throttle management and it becomes a non-issue. Show us a pic of this restored beauty.... I'm sure everyone would like to see it.

Good luck with your resto project...

Dan

Carolina Custom Aircraft

If you fly off tarmac the 13� prop might work on the Kwik Fli but it will be very close. Not sure how it would work on grass though. I always fly off tarmac so prop clearance usually is not a problem.

Here are some pics, no motor in it right now. What do you think about a piped, pumped YS .45 2 stroke? I know that has to have more power than a 1970's era .60. Check out the Kraft sticker and the original chrome rimed wheels. I held the tail up with my dad's old Kraft gold box for the full effect.

More

Tommy,

I believe if I were you I'd put in the YS... I am also a huge YS fan and for the weight, you can't touch the power... I have seen a Super Kaos with retract powered by a YS.45 and it had almost unlimited vertical. The Kwik Fli is a bit smaller than that... I bet you would be happy and any tip clearance problems would go away... but.. Don't be afraid to throw on a 3 bladed prop.. that's what they were designed for and you will see some of the top FAI pilots flying as much as a 4 bladed prop just for braking effect going down... just a thought for you.. great plane to bring back to life..

good luck,
Dan

Carolina Custom Aircraft

Tommygun,

Thanks for sharing the pictures. Someone spent a lot of time building that aircraft. Looks like the wing might have been covered with silk and painted. Can’t tell on the fuselage, might be coated with epoxy and panted but the original had open areas on the sides of the tail. Interesting that the fuselage has filets and a bolt on wing, because the original Kwik Fli III did not have filets and used rubber bands to hold the wing on. Looks like the fuel tank hatch has been modified too and must be held by a screw on the front. Whoever built it did a very nice job and put a lot of air time with it. It has a fabulous patina and if it was mine I would leave it as is. From the AMA number the person that built it would be in their early 60s now unless they were older when they joined the AMA.

From the pictures it looks like it has wood beam mounts for the engine. The original Kwik Fli III only had a little over 3 ¼� from the front of the fuselage to the firewall for the engine space. It was designed that way because Phil used an aluminum plate on the back of his engine that bolted directly to the firewall. The short space limits the type of engine that will easily fit. On beam mounts, most modern 61s will need about 3 ¾� or more with the remote needle valves. The OS 91 is almost 4� plus the space needed for the remote needle valve so I expect you would need to do a lot of rework on the nose to make it fit. Although I prefer 61s in Kwik Flis, some of the 50 - 53 size engines like the Irvine 53 ABC (with a front needle valve) with a pipe would be a good choice.

Yeah, that's where one dilema is. It seems pretty original, so I hate to chop up the front of the airplane to shoe-horn in a .91. If you think that YS motor will work, it might be worth a try first, since once I trim the wood beams to fit the .91, there will be no going back. The fuselage is painted, I can't find this color anywhere other than maybe to get it custom mixed at an autobody shop like someone suggested in one of my other threads. The wing is covered in a strange, older thick fabric covering. It seems pretty good for the most part, but is wrinkled and coming loose on the aft edge of the right wing. I was thinking about just lifting the covering slightly, and spraying underneath it with some 3M 77 sray adhesive. This should provide good results for the time being, since I're really like to avoid having to redo the wing. The other issue is, I can't decide what to do for aileron servos. There is a sideways mounted tray in the center of the wing, and 2 rods run out to 2 seperate bellcranks, I'm wondering if mounting a servo on each wing tip might be better? Or would it be better to just use the bellcrank system? You also mentioned the AMA number, I bought it from a guy at the Lebanon swap meet this year. He seemed to be maybe early 50's? Can you contact someone via this number? I'd really like to know what kind of paint and covering he used. The servo rails are really far apart, definately some huge Kraft gear was the last equiptment used.

Tommygun,

I agree with others that the .91 will be asking for flutter especially with a bell crank system for the alierons [sp] and the apparent age of the airframe. It would be a real shame to loose a classic because of too much power. I'd suggest returning it to origional as much as possible and enjoy it. Best regards. Sugarfox.

I think it has a fabulous patina and I would not repaint it. Just make sure all the wood is sealed to keep the fuel and oil out. If the wing bell cranks were done correctly they should work fine with a single servo. But if there is slop that would be a problem.

3M 77 is not very good in the heat so depending on your climate it will come loose. It melts at around 120 degrees but will come loose with repeated exposure to 80 and 90 degree temps. You might see if you could get some high temp contact cement from a shop that does car headliners and brush it under the lose covering. Depending on how much of the coving is loose CA might work. Possibly pull it tight using masking tape and then CA it down.

I’m not sure if the AMA will give out the names of members by AMA number but you could try. It would help if you explained that you have a very old model and would like to contact the owner. The 60XXX number would have been issued in the late 60s.

Are you saying this model could have been built in the late 60's? I was thinking 70's, but who really knows! That's why I'd like to get a hold of the original owner- now I wish I asked him. Today I weighed the model with the YS .45 and pipe, and threw all the radio gear on top of the wing to get an idea of the all up flying weight. Rough estimate- comes out to about 5.5 lbs all up. The .45 is actually big enough to fit right on the rails with no mods- it may even use the existing holes! I've pretty much ruled out the .91 from what you guys are saying, so now it's down to the .45, or a 70's vintage OS black head max. Can't decide!

I would definitely go with the YS .45 versus the OS .91, I also agree on leaving the airframe as it is. Just sweat the details, make sure you have slop free connections and enjoy. Let us know how the first flights go.

What I was talking about was the builders AMA number that would have been issued in the late 60s.

The Phil Kraft won the 1967 AMA Nationals and in 1968 won the world championships with the Kwik Fli III. It was published in the February 1968 Modal Airplane News. See first image. Shortly there after Top Flite produced the kit. See second image. There was also a kit by Graupner (See third and fourth image) and a fiberglass and foam taper wing kit by Howard Engineering. See the orange aircraft in the last image. I’m currently flying the HE version and have another kit that I have stored away.

Most recently Home Hobby Solutions came out with reproduction kit that is excellent. http://www.rcuniverse.com/forum/m_4221047/tm.htm

I also have one of HHS kits.

At 5.5 lbs and a piped YS 45 you should be good to go for ballistic vertical. Be careful of your CG with the light engine.

Just for fun, here's what the older .60 I have looks like. My father bought it around 75 or so and put it in a RCM/Bridi Trainer 60. His eyes went bad before he could ever fly it, but I took it up for him once. The engine seemed at the time to have good power, but I'm thinking getting a header for a tuned pipe might be difficult. It would complement the "patina" quite nicely though huh? Do you think retrofitting retracts would take away from that?

I have 2 KwikFlys myself, one with trike setup and the other with a "kitbash" taildragger conversion. Trike weighs in at 13lbs (!!!) and is powered by an unpiped ASP61 with stock muffler (it had a HB61 from the late 70s until it went sour with a lack of compression). It flies very well!
The other weighs in at about 10lbs, has a SuperTigre G75 also with stock muffler, and has amazing vertical (not quite unlimited though).
My opinion: leave those ugly ugly pipes off the plane!!!! They look soooooooo awful. You will be fine using a stock muffler and the 91, or anything down to a 61 if you keep the weight down.....
PS: retracts on a KwikFly? I've thought about it....decided not to, though :-)

Regards
Hank

Hank,

There must be a metric conversion problem with your weights! A Kwik Fli III cannot weigh 13 lbs or 10 lbs. I have a Kwik Fli III with a glass fuselage, foam wing and retracts and it is less than 7.5 lbs.

Very nice pic of your Kwik Fli 8178. Looks really smooth with the gear up. Do you know exactly what that car headliner adhesive is called? Is it heavy? You guys have convinced me to keep it original, I think I'll go with the vintage .60- it should turn heads at the field. Hopefully it still runs after all these years of sitting! I'm almost tempted to put the old Kraft radio in it, but I won't for obvious reasons.

I’m not sure what it is called. You just need some contact glue that will glue down smooth and will not have a problem with heat.

TommyGun,
Try 3M Super Trim Adhesive (Part # 08090) or Heads Up Headliner Adhesive. Both should be sold at automotive supply stores.

I went and got some of that 3M super 90 spray, so it's not the 77. It seems to hold the covering down really well.

Finally, you have come to your senses. I think you've chosen wisely, Tommygun!

Pipes and retracts on pattern planes became the norm way after the Kwik Fli's time anyway. And if you really want a ballistic rig, you can always get a design better suited for overpowering (fiberglass fuse, double tapererd wing, swept leading edge, etc.) such as the ones kitted by Dan Hines at Carolina Custom, and others.

Oh! and in response to Miniflyer - there is definitely some error in the conversion from metric to pounds. I would think that in order to build up a Kwik Fli to weight 13 lbs., one would have to: substitute all balsa parts for hardwood equivalents, glass the whole airframe twice, and use twelve coats of paint. Thirteen lbs. is more than double the rated weight of the finished kit as per the designer's calculations. The plane would also be a flying rock.