spinner55

I like light, what is the best engine size in the jbb to keep it light and still allow it to hover?

Spinner[>:]

Gimble Bender

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O.S. .91FX with a mousse-can pipe. Mine hovers great and weighs 8lb 2oz. I don't know how you could make it any lighter without major mods to the airframe. RCAddiction has one with a Zenoah G-23 that has an All-Up Weight of 10lb 12oz and he says it flys like a butterfly! I think I'll get another to try a G-26 on. Hate to mess mine up just to experiment. It looks like it would be an awesome set-up though.

RCAddiction

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The plane has a huge, thick wing. It really flies lightly even with the lightened G23 I'm using. However, my plans show a .75 or .76 (I forget which) 2 stroke. If you can get one that is lighter than the .91FX, that might be the lightest combo that will hover, but the .91 would possibly be a better choice, IMHO.

I was just looking for a good home for a G23. I also wanted to find out if it was possible to use a small gas engine to produce a highly aerobatic, light flying 3D capable plane which flies awesome. You just need to find the right sort of plane.

Gimble Bender

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taildragger21

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I have a new evolution 100 laying around the shop. Was looking for a cheap knock around plane to do some crasy stuff with. At my calculations at 8 lbs. it should hover well with the evo.. What do you guys think..

Zippi

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I was looking at putting a 25cc IE conversion engine on a JBB. Anyone have this setup yet?

Gimble Bender

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TailDragger,
I'm not a big Evo fan, but i've never owned one either. Some of the guys I fly with have had them with lackluster results. But, If the engine runs well it should be PLENTY of motor. This plane would probably fly well on a .60 size engine due to the HUGE wing and light weight. Note: I said fly well, not 3D/Hover well. I say GO FOR IT!! You will absolutely love this plane! It is VERY forgiving. To quote a flying buddy of mine, "If it's moving, it's flying" and he is right. You cannot stall this airplane. Run it straight up and let off the power. When it stops, the nose will fall straight over to level and it's flying again. Unreal. Everything you have read about the great flying qualities of this plane is true.

Zippi,
Yes, several people on this thread have gas engines on their JBB. There are also other threads on the subject of a JBB/Gas engine combo. Mostly everybody has a G-23 or G-26 Zenoah that has been converted to EI. I am about to get another JBB to try it out on. Can't wait to see how it flies compared to my JBB with glow. There should be about a 2 to 2 1/2 pound diffrence between the two. we'll see how the extra weight of the gasser affects the Big Boy.

taildragger21

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We have most always have good sucess with the evo motors. I say the 100 will pull the crap out of it, and still be light. My main thing is I am mostly into giant scale gas. I just want somthing like this to fly because it would be cheap and I could fly the wings off without worrying about a big investment.

Gimble Bender

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You are 100% correct. Be sure and keep us posted with your progress and flight report!!
GB

taildragger21

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Thanks Gimble Bender.. This plane should be alot more fun than my u-can-do was. I will try those 100 ft touch and go's.. Awesome!!!!

Gimble Bender

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I haven't tried that one yet, but landing this plane, especially on a calm day is soooo much fun! I haven't flown mine much because I just got it completed this winter but I did have one calm day and just about all I did was touch and go's. You absolutely can not fly this plane without this stupid grin on your face. It slows down to a crawl and you just grease it in. It's actually easier to land dead-stick than it is running because the plane just want's to keep flying. (if it's not 10 feet high and halfway down the runway when it quits,that is, Ask me how I know!!.) Randy got in the habbit of flying his until it was almost out of gas, Then going WAY up and flying until it ran out. He would then see how long he could dead-stick it. He would fly the pattern round and round until it got lower then dive down and do a loop or some dead-stick snap-rolls before cranking it around for a three-pointer on the centerline. It was funny to watch peoples faces who had never seen him do that before. They would freak out. I think his longest dead stick from the time it quit until wheels-stopped was about 2 1/2 or 3 minutes.

dougwill

Gimble Bender What's the weight of the OS 91? Will be putting either a 100 or 125 Saito in and was wondering if the extra wt. of four strokers is a problem. I like the torque of those four strokers.



Doug

ICE 32 ICEMAN

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Doug,
Don't know the exact weight of the 100 or 125 Saito but on mine I was able to bolt on a 100 to a stock mount and install the servos/ battery/ receiver in their stock locations and fly as is. The balance was perfect. I yanked the 100 off and am waiting for the 125 to come in at the LHS. (My clipped wing version is still sporting a Moki .61. The 125 is going on my 80" stock JBB.) I have a friend that is running a new 125 with a 15-6 APC on it and his Showtime is ballistic. I'm thinking a JERRY'S BIG BOY is going to be a power junkie's favorite toy!
Terry

Gimble Bender

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Doug,
You should have no problem running a saito 125 on it. This airplane is kind of strange that way. It will run on almost any engine you've got laying around with little to no problems with balancing it. The manual calls for a .77 - .91 2 stroke or a .60 to 1.20 four stroke. But just look at this thread, Youve got people running engines ranging from a Moki .61 to a Zenoah G-26 (1.60).
GB
By the way, I'm just a tad tail heavy with the .91 on there and everything is as far forward as possible, but I'm not using the tree mounts so the engine is right on the firewall.

Gimble Bender

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What happened? Everybody leave??

dougwill

Gimble Bender No wer're still here. Just hibernating here waiting on spring.. What's hid in the foam up front in your pic? Something up underneath fuel tank and what battery are you using?



ICE 32 ICEMAN Tell us about that Saito 125. Have you fired it up yet?

Doug(cold in Ohio)[8D]

Gimble Bender

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Doug,
Are you talking about the blue thing facing you as you look at the pic? If so that is a Fromeco regulator. I don't have anything underneath the fuel tanks. I'm running a Fromeco "relion" 2400mAh Lithium-Ion battery and a Fromeco Super regulated Relia-Switch regulator. This is the first set-up like this I have had and I love it. It is a 2400mAh 2 cell battery that weighs 3.3oz!!!! I had a JR Sport 2700mAh batt in it before I shelled out the bucks for the Fromeco set-up and it was like having a brick in there. It weighed 8.4oz!! Had sub-c cells and took up a lot of room. This was the way to go, lots of power and endurance in a very light-weight package. But keep that in mind when you price them[8D]

ICE 32 ICEMAN

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Doug,
Haven't fired it up yet. I have laid it side by side with the 100 and they are identical. I want to take it apart to look at bore/stroke differences but I'll probably wait until after I get a little run time on it.

When my son and I walked into the family center at church this past Sunday, the preacher took my son aside and asked if that had been him flying model airplanes on the church athletic field earlier in the week. He was a bit reluctant but told the preacher that indeed it was him. I thought he might be in some kind of trouble or something but the preacher started in raving about how well his planes looked and how well he flew them. This next Sunday we have a church wide barbeque after services that will last for pretty much the rest of the afternoon. He has asked us to bring several planes and put on a little airshow. We usually have about a thousand people that come to this yearly get-together so we are going to break out the BIG BOYS and a few electrics and a heli and put the sport of aero-modeling into the spotlight!

I haven't run the 1.25 yet but might have it ready for this little airshow. I'll let ya'll know how much more lively the BIG BOY is with the 1.25 on it. I still can't believe how much size SAITO packed into the 100 case! When you realize that the 1.20, 1.50 and 1.80 are all in the same size package and then along comes a 1.25 in a smaller size case than a 1.20, you gotta wonder what this thing is going to do! I'll let you know......
Terry

suitcase

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I'm interested too ICE. Especially in how it's mounted (inverted or not) and tank location and how well it runs with same. I'm thinking the 125 or a YS 110.

RCBOZO

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suitcase didn't you have the G23 setup? Are you thinking of replacing it with a different motor?

Gimble Bender

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Suitcase,
I saw your G-26 on the market for sale. What made you want to change engines? Did you not like the G-26 on there? The reason I ask is I just aquired another JBB and i'm going to set it up with a g-26. My first JBB is still going strong with the O.S. .91FX on it and I bought Randy's from him to experiment with. Just curious.
GB

suitcase

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Mine is the G26. The engine runs really good but would dead stick sometime. RVator yanked the firewall out of it after a dead stick. I repaired it and moved the firewall back an inch. In the meantime I ordered the smaller carb that was on the G23 and installed it on the engine. I went to the field without checking the CG and it ran really well but the CG was too far forward because of having removed some weight that I had on the tail. I needed several cliks of ele trim and it made it fly somewhat heavy. I think that the CG being too far forward made it feel that way and that it lacked the power it had with the bigger carb. It started very well and ran without a single dead stick. It seems to have the same RPM and idles very slow, slower than I was willing to leave it set at. I had decided to try and sell the engine to get a Saito or YS to put on it, just to lighten it up. The G26 flys the heck out it, so I think it's just the CG needs to be corrected to get back to the way it used to fly.

Bottom line is, the BB will fly great with the G26 and I was completely satisfied with it. Except for the dead sticks. Which normally came after a long spin or loop. The WA167 carb I think has cured that but time will tell. The stock carb is extremely touchy to adjust, especially the low needle and thats the one that causes the engine to die at idle when airborne. I'll keep the engine on it without reservation too, I still love the plane. I was just looking for a change. I'm still waiting to fly my Mayhem for the first time. Gotta learn about them YS engines now.

gbdvorsky

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Thought I'd throw in another JBB with a gas engine to feed the conversation. Been lurking on this thread for the better part of two months before I decided to get a JBB, and I'm really glad that I did.

Had the maiden flight yesterday on my JBB with a Brillelli 25 GT Toro conversion. This is my second gasser, and I'm in it for around 1/4th the cost of my Wild Hare Edge, which is a pretty economical build in itself. All in, I'm guessing at $560 for everything in a giant scale, gas engine sport plane that I can flog pretty hard -- and by every indication so far, it it can take a bit of abuse.

I don't have a good scale, so I can't tell exactly what it weighs, but I'd guess in the 13-14 lb range. The maiden was uneventful, and it flew hands off with just one click of right aileron. It lands at the pace of a brisk walk, and the guys at the field were simply amazed. It loops in about 1 1/2 lengths of the fuselage, and is nearly impossible to stall. I still need to increase the rudder throw for a better knife edge given the big chunk of aluminum on the nose. Still breaking in the engine but I am expecting great things. Scott Ellingson at Brillelli is great to deal with, and for $165 to my door, you can't beat this engine.

I think I sold at least one JBB at the field yesterday ... can't wait to get back to the field.

The setup:

Brillelli 25cc GT -- $165
Jerry's Big Boy -- $150 (eBay Auction)
8 Cirrus 605's -- $80
Receiver+Crystal -- $50
2700 mah NiMH -- $30
Misc Hardware/Extensions/Y's/Prop -- $85

Gimble Bender

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Man I hope that is a really high guess!![X(][X(] My glow JBB weighs 8 lbs 9oz!! I'll post when I get my gas JBB going and can tell you how much it weighs.
I expect it to be in the high tens (fingers crossed)
GB

gbdvorsky

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Proof that I'm a bad judge of weight!!

I broke out the trusty bathroom scale and it comes in at between 11 and 11 1/2 lbs. No wonder it flys so nicely!

If it had EI instead of a magneto, I imagine it would be getting really close to the 10 lb. mark.