Jim Hargett

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Hi Guys,

I am seeking some advice. I have purchased a World Models 1/4 Piper J-3 Cub and now need to
select and purchase an engine. FYI: the flying weight of the plane is 14-16 lbs, and the recommended
engine size is 0.91 cu. in. displacement for 2-stroke, and 1.20 - 1.60 cu. in. for a four-stroke.

I want to install a gasoline engine into this plane. I am seriously leaning towards an OS GT22, though I
am aware there are lots and lots of other possible choices. I like the OS GT 22 mainly because (1) I have several OS
nitro engines and they have been super reliable; (2) the total weight of the OS GT22 is 35.24 oz, which is
lighter than most other comparable gas engines on the marker; (3) the OS22GT seems to be very compact and o
thus cowl friendly, and comes with a Pitts-style muffler, which I like; and (4) has a two-year warranty.

Any thoughts or suggestions would be much appreciated! Thanks! If you recommend a particular gas engine
over the OS GT22, please be as specific as you can with your reasons. This would help me a lot.
Thanks again!

Jim Hargett
Guilderland, NY

FlyerInOKC

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I have an old SIG Clipped Wing kit in the attic I hope I remember how you did this when I build it. It looks like a great solution for getting the alignment correct.

mustangherb

My Feedback: (6)

This is shaping up to be a great looking plane. I just hope I can do it justice, as I am building it for a friend of mine.

John_M_

What is your budget?... I like OS engines as well; kinda favor the 4 strokes... the OS GF40 is a nice "GAS" 4stroke http://www.osengines.com/engines-air...800/index.html http://www.youtube.com/watch?v=Gsk7vV4E5Zs ; it may be a bit too much engine @ 3.75 hp output, but you don't have to use it... it swings a scale prop 18-8 and up... Saito also makes some nice four stroke engines, but their later engines use "AAC" chromed plated aluminum valve seats, which don't lend themselves to longevity as did their earlier bronze valve seats.... http://www.horizonhobby.com/products...ne-bo-SAIEG30B

I've got an OS FT 160 twin in my cub, which will be converted to CDI ignition, but still run on glow fuel... I would definitely get something with a decent power output, I call it "just in case power"; you don't have to use it, but its there if you need it... I haven't run a 2 stroke in years so I couldn't give you any feedback, but I'm sure there are plenty here running the 2 stroke "GAS" engines that will comment.


John M,

Jim Hargett

My Feedback: (1)

John M,

Many thanks for your thoughtful comments and useful advice!
Very, very useful!!!

Jim

John_M_

Sure no problem Jim...

A lot of people are running the DLE "GAS" engines (2 stroke) in the 1/4 cubs; usually the DLE 20 through to the DLE 35..... http://www.dle-engines.com/... I've only read forum threads, but from what I've read on the forums, they are a good engine.

That OS GF40 is of course a 40CC engine... but being a 4 stroke, I don't think it would be too much for a 1/4 scale aircraft... I think it would be a nice match in a 1/4 scale super cub or clipped wing cub... for a 40cc, its physical size is comparable to some of the 2 stroke engines like the DLE's... but you do need to take physical size of the engine into consideration.. i.e, is it going to fit in the cowl without having to cut too much of the cowl away; and how, and where the exhaust exits; i.e, rear exhaust / or side exhaust.

800 usd for that OS GF40 isn't cheap, but it sure does seem to perform well... if you search on youtube for " OS GF40 "; there are a few videos demonstrating its performance... it got me drooling, lol.


Here's a thread on the OS GF40

http://www.rcuniverse.com/forum/gas-...0-4st-gas.html.


Another of his comments regarding using it on a 1/4 cub or super cub.

http://www.rcuniverse.com/forum/gas-...l#post11518894 Post #19


John M,

acdii

I fly a DLE 20 in my 4*120. Good running engine, have 2 gallons through it so far, not even fully broken in yet. It sips fuel, a 14 ounce take lasts me longer than I care to stay aloft. 25 minutes flying and still had 3/8th tank left. I think the only downside to it is the 2 stroke chain saw exhaust.

Jim Hargett

My Feedback: (1)

Thanks again, John. You raise some more good points, especially the size of the engine viz-a-viz
the space available in the cowl. For my World Models 1/4 scale Cub, I think I will probably go with
the OS GT22. But for my next project--a 1/3 scale Cub--it seems that the OS GF40 would be an excellent
choice.

ACDII: Thanks for your comments. I am looking forward to the longer flight times with my 1/4 Cub,
the chainsaw exhaust of the two-stroke OS GT22 notwithstanding!

Cheers,

Jim

acdii

Worked on my Cub last night, only thing left to be covered are the ailerons which I am going to do after the wing is fully painted to make sure they fit with the covering on. I think I had a reaction to the Dope though, woke up in the middle of the night itching like crazy and this morning covered in tiny red spots. Never happened before working with Dope, so wonder if it was something else that I became allergic to.

FlyerInOKC

My Feedback: (6)

It can happen acdii! I have to use foam safe CA because I react to the original stuff but now the foam safe is starting to aggravate my sinuses a bit. I have started tapering off and using more PVA like Titebond II.

John_M_

I'm sure the GT22 will be more than adequate based on whats being said using the DLE 20... with 2.66 hp, should be plenty to pull a 14-16 lb aircraft around.... originally I had a Saito FA130TD (4 stroke twin) in my sig 1/4 cub... the cub weighed in a 16.5 lbs... the 130 produced 1.9 hp swinging a 16-6 propeller... it had plenty of power to fly the plane, but not quite enough to do vertical maneuvers... I put a CDI ignition system on it and stepped up the prop to a 18-6, and got enough pull out of her to hang her on the prop, but just barely... I'm hoping with the OS 160 CDI I can get a bit more performance out of it... when I'm finished with it, it should produce around 2.5 hp with a 18-6... I'm not looking for power to do 3D, just enough to pull up to do vertical maneuvers and to pull out of stalls.

A 1/3 cub with that OS GF40 4 stroke would be on the low end of the power scale; great for scale flying, but you'll need a bit more, like 100cc (4 stroke) on a 1/3 cub.

John M,

John_M_

Coming along nice acdii... I hope you ventilate the area you work in well... breathing that stuff can be harmful... I use to do the ol tissue and dope on my free flight planes... one time I got complacent and had the garage door closed; after about 15 minutes my head was swimming like I was on lsd, then came a wicked headache... never do that again, lol



John M,

acdii

Thanks. The dope doesnt make me feel high or give me a headache, but it never gave me a rash either. I dont know if its something I ate or if a reaction to the dope.

John_M_

Well maybe you had a reaction to the acetone... that stuff gets readily absorbed into the skin and into the blood stream; not good for the liver... that's why I ovoid using the silk / polyester & dope covering methods.

acdii

I have been using acetone for a long time, without any reactions, so I don't think it would be that. BTW, did you know the body produces acetone? If you go on an Atkins low carb diet, your body goes into acidosis, which is where i burns off stored fat to make up for the loss of sugars in the food. Byproduct of this is acetone. You can tell you are in full acidosis when you smell acetone when you pee.

It's not the first time I used dope, or thinners, so not sure what caused it. One thing that I did change yesterday was using Tylenol PM instead of Advil PM, so it could be a reaction to acetaminophen/diphenhydramine blend, where the Ibuprofen/diphenhydramine blend didn't have a reaction.

John_M_

Really !!, I did not know that... I was told to always use chemical resistant gloves when handing solvents and that acetone was one that is easily absorbed into the skin... maybe that's why it gets absorbed to to the skin, because the body produces it... I can only imagine what it feels like passing acetone!!

Thanks for the info, now I know how to make my own acetone... next time I get cited for peeing in public, I can just tell the cops I'm removing graffiti from the wall, lol ... from the sounds of it, you must be involved in the medical industry in some way?... I use plan ol aspirin, don't like tylenol... I ovoid any medication; over the counter or prescription unless its absolutely necessary.


***EDIT*** now I'm having weird thoughts about peeing into flames, lol... I'm just twisted in my old age.

bigbird3

Hi John M., Haven't been on for some time but have been reading the blog as it goes along. Speaking of chemicals, MEK is a very poisonous thing to use also. It is known as a compounding poison. In other words, it will build up in your system and then become toxic as where arsenic is not. It will eventually leave the body in the pee and poo and you will recover if you haven't had a fatal dose.
On the engine note for the 1/4 cub, I have used the chinese 26's and it has very good power and is light weight. On the third scale cub in my gallery, I used a G-62. Lots of power and as you said, you don't have to use it but if you don't have it, you can't add it in a stall!
Keep up the fine blogging guys. I really enjoy it.
bird.

acdii

Slight correction, it is Keto-Acidosis. Acidoses is a bad thing.

I had been on a low carb diet last year, lost 50 pounds on it, and is where I learned about the body producing Acetone. Anyhow, I sure hope it wasn't working with the dope that caused my rash. It i nasty and has kept me up for the second night in a row, the itching just wont stop no matter what I put on it or take. Benedryl is supposed to stop it, but it isnt working,. trying to get a doctors appointment today to get it looked at and get some sleep aids.

Super08

My Feedback: (2)

My wife did that diet a few years back. You can even smell it on their breath.

John_M_

Hi Bird

Also polyester resins used in fiberglass work is very toxic... I've always used chem gloves when working with solvents, but I ovoid using solvents unless need be.

Whats the G62---- 62CC's, 6+ hp 2 stroke?... that's about right for a 35 40 lb plane, but to get that in a 4 stroke, I would assume a bit larger displacement would be in order... I know large displacement 4 strokes above 50cc's are hard to come by, which is one of the reasons I haven't gone to the 1/3 scale yet... I'm a 4 stroke nut, so I would have to have one on the nose that's for sure... the OS FT300 is a nice 4 stroke engine, but it only produces 4 hp... and the Pegasus FF320 only 4.1 hp; the power to weight ratio of the 320, is just a boat anchor if you ask me (2 160's in tandem)... I've seen the FT300 on a 1/3 scale BalsaUSA cub... it of course sounded great, and seemed to have fair performance, but I still think its marginal for the weight of the aircraft... if I got into the 1/3 scale, I guess I would have no choice but to go with a 2 stroke gasser with plenty of reserve power to get me in and out of trouble with, lol.

Yeah, I have seen so many situations with other rc pilots where a stall occurs, and if they had a bit more power they could have recovered from it... in the past I've had the tendency to be marginal on power... but as I get older my response time has slowed some what, and there has been times where brute force could have come in handy, so more is always better to some degree.



John M,

John_M_

Ok, thanks for the heads up, I had no idea the body could produce acetone... makes you wonder about our existence, certainly seems more like a design to me.


BTW Super08... send Cub Man a PM and remind him to assign you a Cub brotherhood #


John M,

bigbird3

John M, the G-62 is a Zenoah brand. It is not a CDI engine but a magneto. very compact mag and very efficient without the CDI and battery pack for ignition. Don't mind all of that extra stuff as long as you have the room to put it. Most of the time you don't! Not sure at this point what the HP is on this engine but easily looked up at the Zenoah site.
As for the OS 320, I have one and bought it for the Balsa USA third scale cub that I never finished and traded for my Hostetler Stinson SR-10 kit that I am now building. I had it for quite a few years before I finally put it on my GP third scale Pitts! What a beauty! It was a fun plane to fly believe it or not at 23 pounds! Really! Never had an 'unfriendly' moment with it. It was a nice plane and the sound as you said is really great! I actually ran it with a 24X6 prop and it handled it fine. You just have to tune it slightly on the fat side not to burn it up and keep it cool. I have quite a few pics if you are interested. The thing I try to do is fly scale and if you have a high revving engine it is hard to do scale take offs and flying. Over propped engines tuned fat will render a nice scale result. It is a risk I know but........learn to fly in it's boundries instead of being a speek or power freak. Just my prefered modis of aparandi!

The polyester resin if I'm not mistaken uses MEK also in it's formula. It is also an ingredient in epoxy as a catylist agent. Less MEK equals more cure time. More MEK and you have five minute epoxy.
bird.

bigbird3

I have put the pitts in my gallery. It was a fun project for sure.
bird.

John_M_

Ok Bird, just took a look at your pic's... very nice looking pitts Bird... I must say that 320 does look nice, but I would go with the 300 before the 320 specially on a cub... unfortunately the width of the 320 isn't wide enough to extend out side the cowling on a third scale cub... but what about taking two 300's and making a 100cc 4 cyl Pegasus; we'll call it the FF600... now that would be just right for a third scale cub... a bit on the heavy side, but, I'd rather deal with a nose heavy plane than a tail-heavy one... would pull a 35 lb cub around quite well.

***EDIT***

That's why I prefer the 4 strokes over the 2 strokes... lol, my ability to fly within boundaries have almost but gone... I like having that extra margin just in case I have a brain f**t and make a mistake; but you are right, a good pilot knows his aircraft... but I didn't say I was a good pilot lol... when I go out to the rwy to takeoff, everyone seems to head back to the pits... at first I thought it was me, maybe I smelled or something, but then one time I called out a "dead stick" landing and everyone hit the deck... "you got it John, you got it !!" one guy exclaimed... then I look down and it was my inlaw, lol... I said to him "I'm not that bad am I ?"... he replies, "that reminds me I need to up date my will"... damn, that's family for you lol.


BTW, just noticed those stitches in your left hand... wow, that is one serious incision !!


John M,

3136

acdii, how are you going to paint yours?
I used sig koverall for the first time and just went with rattle can paint, but I forgot to use a primer and it is relatively easy to scratch off
I actually had a bugger of a time building this plane I'm starting to hate it, several times I nearly smashed it against the wall.
It's an old pilot ok models kit, glad they don't make them anymore, I normally love making kits and can't wait to get building, but this one has tried my patience.
I'll probably smash it on maiden...... bloody thing!
I'm tempted to kamakazee it into the ground, then I'll buy a sig kit.