Ben Buckle JR 60 (Electric version)

[bill4.0]

i just finished this kit and have about 25 flights on it...i have a few questions about motor and prop setup as well as a battery question....im running a 550 mabuchi with a 2.5 to 1 gearbox and using a 12x6 apc prop...battery is a 7 cell 1000mah sub c pack......im getting about 8 to 12 minute flights as long as winds are light.......but it seems a bit sluggish....takes about 40 to 50 feet of wide open throttle running down a paved surface to get airborn......once up it flies great.......a real slow but constant cruise........am i over or under propped??? or could i do better with an 8 cell pack of equal or more MAH.......anyone with advice please share a bit....im new to the rc sport and doing it all by trial and error.....thnx for the help...bill

[qban_flyer]

As with all Ben Buckle's planes, yours is a very pretty one. I like your color scheme as well.

Could you tell us what the AUW of your model is? Without knowing its total ready to fly weight it is difficult to make recommendations on what you can do to improve its performance.

BTW, I have a Ben Buckle Radio Queen. :)

[bill4.0]

i weighed the plane again and its 4 lbs even.....wing length is 60 inches...wing chord is 10 inches.....any help on a prop and battery recommendations are very much needed......i will add that i want to keep it with the 550 brushed motor and cant afford to go brushless and wont consider LIPOS.....I CRASH TO MUCH!!!!!L.O.L.....

[qban_flyer]

Just sent you a PM.

[Sky Sharkster]

Hello Bill4.0, Welcome to Wattflyer! Based on the info you posted, I ran a few numbers through P-Calc (Diversity's free online motor calc) and it looks like the prop is about right; But the best static thrust I came up with using your data was about 14-15 ounces! Changing to an 8 cell 1000 mAH battery boosted it to 18 ounces with the same prop. This means the power-to-weight ratio is 1:4 (currently) and using 8 cells would be about 1 to 3.5, still not overpowered but better. The 8 cell pack would be a good place to start, unfortunately that's likely the maximum number of cells the 550 will handle (9.6 volts).
You also mentioned the motor has 25 flights on it; Of 8-12 minutes each. Using 10 minutes as an average, that's 250 minutes, or about 4 hours. The motor is at or past it's typical lifespan. The first order of business is to buy a new motor and break it in using the water break-in method. If you get an 8 cell pack, cycle it a few times at low amp draw to break it in. Make sure you're using good quality connectors like Deans Ultra's and balance the prop. These all may seem like trivial adjustments but you're dealing with a marginal power-to-weight factor and even a gain of 10% power will make a big difference in performance.
If you're determined to stick with brushed motors and conventional batteries the only other variable is the gearing; Is it possible to raise the ratio? That and a bigger prop might help also.
Good luck!
Ron

[bill4.0]

thanks to all for the help and advice.....soon as funds make them selves available ill be using all your advice and recommendations to get my plane flying the skies in tip top flying fashion...anyone know where a upgraded 550 motor can be found at reasonable prices???? the gearbox recomendation is very much possible as the one i have can have the gearing changed but way of a different spur gear on the motor.....i can take it as high as 3.8 to 1.......ide like to find a great planes 550 thrustmaster for a good price........anyone have one???? i did motor calc and it seems that motor alone would boost my watt per pound into the good flying catagory.....she flies on my current setup but just seems real sluggish......anything i do as upgrades can only make it fly better right???? thnx to all for the help and advice.........being new to this sport i can use all i can recieve.........thnx...bill4.0

[qban_flyer]

As I recommended in my PM, the Kyosho Magnetic Mayhem can be had for under $25. I used it myself direct as well as geared. Do not use the Mayhem with a pack larger than seven cells if you want it to last.

If you are going to use it geared get the one marked "Reverse Rotation" on the label as it is properly timed for gearboxe use. As Ron has stated above, a higher gear ratio would allow you to swing a larger propeller as well.

Let us know how it goes. :)

[eflight-ray]

Bill4.0

I'm currently flying my Majestic Major on a Magnetic Mayhem, Olympus 2.3:1 belt drive, an APC-e 12x8 prop and 7 cells, (3300mAh Nimh).

Now she's 88" span and flying weight is 6lb 7oz, so brushless isn't neccessary for vintage. But a standard Mabuchi 550 might be struggling a bit, perhaps a Speed 600 7v2 or one of the car buggy motors might help.

Edit - Do remember that 'sluggish' is what vintage models do, more power just means more down thrust.

[bill4.0]

i appreciate all the excellent help and advice ive recieved.....unfortunantly ole ben took a bad nose dive tonight so it wont be flying anytime soon.....if i decide to rebuild ill be sure to use the recomendations ive recieved.........im thinking it was a bad servo as the flight the other night went as all others did.....tonight shortly after launch and at the flying height ive been using,,,,it went nuts and went for the dive,,,,i tried to compinsate as much as i could and managed to get the nose up a pinch before impact.....broken gear drive,,,,shatterd 12x6 prop,,,,munched up nose and various fusealage stringers broken......not totaled but a major setback as im unemployed and money is getting a bit tight.......ole ben will fly again...just not sure at this point as when.........thnx again for the advice.......bill4.0

[qban_flyer]

Sorry to hear that bill 4.0. :o

[bill4.0]

I once again have the opportunity to fly my Ben Buckle Jr 60 again.....after his unfortunate rough nose landing recently,,,i have managed to rebuild my plane to almost new condition....ive since added a new motor..which was a present from my girl friend annie....i am now running a brand new Permax 600..geared 2.5 to 1 ..11x7 master airscrew prop....and i am stil using a sanyo 1000 mah pack......i plan to try the gear box as 3 to 1...use a APC 12x6 electric prop and see if i can get a few more minutes of flight time........current setup seems quite adequate for about 6 to 10 minute flight if i get to flying height and cut back to half throttle......its flys nice and level....and has descent climb rates.......ill use all previous recommendations to get it flying better as soon as the pocket book allows it.........i must say this is by far the easiest plane ive flown and it makes a real nice trainer.......thanks again to all who have helped me with the advice....bill4.0..PS.... has anyone else ever hand launched this plane????I tried it awhile ago and it gets it flying alot faster than trying to R.O.G....works great when the wind is still.........

[15bert]

FWIW - I have just re-motored my J60 with an Astro 05G brushed with 10 x RC2000maH nicads driving an APCE 12 x 6. It pulls 32/33 Amps WOT about 350W on the Whattmeter which seems a bit much but I have to take off from grass and our strip isn't very long.

I maidened it with this set-up this weekend and it was good! I got a six minute flight out of the pack but I wasn't trying for duration.

I did try it the week before with 8 x 2400 nicads but very nearly ran out of room on takeoff.

On the ten cell pack she got off ok with no wind and cruised at about 1/3rd throttle, very reminiscent of the '50s, when these 'planes used to fly FF on quite small diesels.

I'm hoping for a bit more duration when I take her out again, the 10 cell pack hasn't been cycled for a while so it may well improve. A bit more throttle management will help too!

Bert

[RogerQ]

Why not try a geared speed 400 motor. I bought a cobalt 400 cheap (can't remember exactly how much, less than 25.00) put on it a gear, and then attached a gear box. It pulled a 4 lb plane with no problems, with an 8 cell ni-cad. And again, I cant remember how big a set of batteries it was. The thing is, for less than 35.00 you can have a powerful, smooth running set up, that will fly your junior 60. I have one also that I bought in England, and plan on the geared, cobalt 400. Roger q

[RogerQ]

An addendum to what I said above about a speed 400. I bought a Wattage "Super 400 Cobalt Motor-27 T. Put it on the small, not the large, the small Master Airscrew gear box. A great Combo. RogerQ

[bill4.0]

thanks again for all the excellent recomendations to get the junior 60 flying at peak performance....rogerq....what size prop are you running with the gearbox and what ratio??? soon as im able to invest in a few more upgrade options ill try to use a few of them to see what works the best as far as how ide like junior to fly......main goal is to be able to R.O.G. a bit easier and less distance than it currently takes......much better on my current setup of the geared 600 but im thinking it should be able to lift in a shorter distance......ive said this in previous posts but must say it again....this is by far the best flying plane ive built and flew to date......my next will be a Black Magic that ive read all about on this site and it too looks to be a very sweet flying plane.......thnx again to all who have added some excellent advice and recomendations......

[RogerQ]

Bill: I have run with two props: both electric: an 11X8 and a 12 X 6. both seemed to work well, although, as one would imagine, a bit faster with the 11 inch prop. Rogerq

[RogerQ]

Bill: question: where did you get the Black Magic? I have heard of it, but not seen much about it. Thanks. Rogerq.

[electricpete]

I have just read about electifying the Junior 60. I was unable to quickly get a junior 60, so bought a super 60 instead, but had trouble finding a round tank so have tried a square one, someone sugested a 1600maHr tank which made me think.

Is the super60/junior60 simple to convert
Would aa Align trex brushless 400 motor suit (another unfinished project)
Are there any lightening measure required in the fuserlage
Is the motor just bolted at the front on a new metal plate in the place of my thunder tiger 25 .

I have started the Super 60 project as I am having trouble landing my Arising star, and am looking for a model that should be able to land itself.

Peter

[15bert]

Peter,

IMHO You will need more power than that, at least a 600 geared brushed motor on a 10 or 11 x 6 prop and ten cells.

If you put a piece of 3/16 ply across where the IC engine used to go and make up a 'U' bolt from a piece of 2 or 3 mm threaded rod which goes through the existing mounting holes it will work. That's what I did with my ex-IC Junior 60

HTH

Bert

[electricpete]

Thanks for the help. I have an unused cobalt 600 motor and gearbox, about 3 to 1, I think, I beleive it will take a highish current. Will I beable to carry 2400 nicads.

Peter

[15bert]

Peter,

The Super 60 will be able to carry 10 x 2400 cells with ease. Be careful to get the c of g right, you will need to get the cells at the front of the 'plane - if necessary add lead to get it right. The Super 60 is a sweet flying 'plane if the C of G is in the right place. Do make sure that the battery cannot move in flight.:eek:

If you are building it from scratch it shouldn't be too difficult, with my J60 because it had been built for IC I had some problems so I made a hole through the front bulkhead underneath the motor and I feed the battery pack through the front of the 'plane. They are held in place by a velcro strap.

The Super 60 has a longer nose IIRC than the J60 so you may be able to make up a squarish-shaped pack to fit in the space behind the motor, where the tank would go for an IC. This would be better than my arrangement which is a bit difficult when connecting the pack to the ESC.

HTH

Bert

[electricpete]

Thank you. I think I shall finish theIC model first and then make another fuz for Electric. I hope I will have managed an assisted landing by then.

Peter

[electricpete]

I was wondering if to fit the Dualsky (.25Cu Equivalent), brushless motor, but it is rear mounted and was wondering how to mount it. I have made anotherbasic frame but not added bearers, or block round the nose. I think I will run off a 2000maHr 8 cell Nicad , probably mounted from the front.

What Volts and current have others used.

Peter

[electricpete]

Sky sharkster what details did you put in to Motor calc and I have just trying to trial it but not very familiar with it, Can you send the data.

Peter

[Sky Sharkster]

Hello Peter, Welcome to Wattflyer! I used the free Electric Calc from FlyDMA (Diversity) here:
http://www.brantuas.com/ezcalc/dma1.asp
Starting with Bill's specs, he was using the 550 Mabuchi, 2.5:1 gearbox, 12 x 6 prop, 7 x 1000mAH battery pack.
From the top of the DMA Electric Motor Calculator page, scroll through "Batteries", the closest I found was the KAN 1050 NiMh, under number of cells, erase "3" add 7 (for now), under "Motor" scroll to Mabuchi RS-550, "Gearbox" erase "1" add "2.5". Under "Prop Diameter" erase whatever is there, add "12", "Pitch" erase/add "6". Don't click "enter" after you add/change stuff, just leave everything in the window the way you want it. When it's all ready, click on "recalcuate".
I like to print out each page so I can compare. Change the "Battery" cell count to "8", recalcuate. More thrust, better efficiency, slightly less run time.
Now change gearing to 3.8, recalcuate; The numbers won't look too good, since this prop is way too small for the increase in gearing. Start increasing prop diameter, I got up to a 16 x 5 or 6 before I started getting some decent numbers, the efficiency was near-max, run times were good, watts in was respectable, prop in-flight thrust was much higher.
The run times aren't really applicable since it's based on "Full Throttle Duration" but it will be a good comparison for the changes.
I like to have a list of available prop sizes handy, there's no sense running numbers for props that don't exist! Same for batteries, stick to the ones you have or can easily get.
It's fun, but addicting! Also, the calcs aren't gospel, they have to be combined with experience and real-world testing. They can provide a start but the rest is up to you.
The photo of the "Dualsky" looks like it has the "X" mount typical of most outrunners. If so, you can mount it flat against a ply firewall, like a radial. There are screw holes in the outer end of each "arm".
Good Luck!
Ron