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Underpowered burrito. What can I expect?

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Underpowered burrito. What can I expect?

Old 08-09-2004, 05:00 AM
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Default Underpowered burrito. What can I expect?

I thought I was going to have more than enough money to put together a great burrito setup..... unfortunately I had to dump a bit of money into my motorcycle, and that took away from my burrito funds. []

Can the burrito fly on a budget BB .40 engine? In this case, a magnum XL 40A... Any ideas on how I can expect the plane to fly with this underpowered mill up front? I suppose most 3D is out of the question?

The radio gear could be considered standard, with 4 hitec standard servos, a HS-55 on throttle, a 6 volt 1500 mAh NiMH, or alternatively a 6 volt 600 mAh Ni-Cd. If it would help, I can pull 2 HS-81's out of my HLG for the ailerons.

Thanks in advance.
Rico
Old 08-09-2004, 05:23 AM
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Default RE: Underpowered burrito. What can I expect?

I'll be interested in the answer to the question you pose too -- since I've just ordered a Burrito (don't worry OMP, I'll probably order an 540 or Katana from you once the 3D bug bites :-) and plan to fit it with a TT GP42 -- at least for starters.

Looking at the servo issue, I see that many people suggest the Hitec HS425 or HS475 servos since they're cheap and quiet strong -- but are they fast enough for 3D?

I put an HS425BB, an HS5475 and an HS81 on the bench beside each other today and just compared the speeds. Boy those HS425's and HS5475 (aka HS475) servos are *SLOW* and I see that the specs quote them as being around 0.2-0.23 seconds for 60 degrees movement at 4.8V. By comparison, the HS81 (at 0.11 seconds for the same 60 degree movement) is blindingly fast.

Surely having slow servos must make things like hovering noticeably harder -- even a quarter of a second sounds like a long time when you're balancing a plane on its tail just a few feet above the deck.

I wonder however, whether the HS81 would have the grunt for a .40-sized 3D machine.

I realise they're not moving very fast, but those control surfaces are *huge* and with all that movement the load on the servos must be high, even at relatively low airspeeds. Has anyone successfully used the HS81MG (I wouldn't dare use the nylon geared version) on such a machine?

Right now I'm thinking HS 525MG or maybe HS625MG -- perhaps even the HS5245MG for those not on a budget.

Do you 3D fliers consume many gear-sets in a season?
Old 08-09-2004, 05:45 AM
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Default RE: Underpowered burrito. What can I expect?

I got a deal on 6 HS-422 servos. They don't seem all that great, but the price was right. I'm going to run them on 6v, and they run 57 in/oz and .16 sec/60 deg. which seems acceptable but far from spectacular.

I may take 2 of my HS-85MG+ servos out of my lite machines heli, and put the regular HS-81 servos, or buy 2 more. The HS-85MG+ servos are great, they're ball bearing, metal gear, and they've got 42 in/lb and .09 sec/60 deg (at 6v) I've never broken a gear, and they've lasted quite a while in my heli.
Old 08-09-2004, 07:20 AM
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Default RE: Underpowered burrito. What can I expect?

NO HS81's on a Burrito's control surfaces.... Thats just lookin for trouble. Stick with some good full size servos on the ail and rud/ele. Put the hs81 on throttle.

If you build light enough, the .40 might be enough punch. I'm thinkin its worth the extra bux to get the .46 and a $12 Tower muffler. That should surely be enough kick to bring it into its own...
Old 08-09-2004, 07:24 AM
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Default RE: Underpowered burrito. What can I expect?

85s are ok, 81s are throttle servos at best. I doubt you would get one flight on an 81. Best bet on Burrito is standards. The are plenty fast enough, especially getting started. Odds are you'll be using expo any way, which does what? Slows down response!!

The motor, well, it'll fly. Probably harrier, I doubt it'll hover unless you get it really light. But you might be surprised, if you build it light and go with lighter gear, it might work. Let us know!!
Old 08-09-2004, 07:34 AM
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Default RE: Underpowered burrito. What can I expect?

I'd agree with the responces listed here.... HS-81's on control surfaces is not a good idea.... Standard servo's will work fine. I wouldn't use the HS-55 on the throttle.... The vibration will kill it. Go with a HS-81 or HS-85 for throttle.

As far as power goes, a .40 bushing engine will fly it, but I don't think you'll be able to do much hovering with it... A mousse can muffler would help the power, but you're better of going with a .46 sized motor. The TT .46 is pretty cheap... You can even check out the Mecoa .46.. I've seen a new one out there the SK .50. It's going for around $60... The Super Tigre .51 is going for around $80.. You could probably pickup a used OS .46 for around $50 - $60 here on RCU.

XJet - Your Burrito is shipping out this morning via Air Mail. Thanks for the order!
Old 08-09-2004, 08:14 AM
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Default RE: Underpowered burrito. What can I expect?

You could probably pickup a used OS .46 for around $50 - $60 here on RCU.
Yep. Just picked up a 46 here on RCU Marketplace for $35. It's in fantastic shape.

Just start looking.
Old 08-09-2004, 08:23 AM
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Default RE: Underpowered burrito. What can I expect?

Thanks for the tips.

I never thought about the vibation killing an HS-55...

I just want to get the plane in the air for a month or two until I get the money for a better engine. Just fly the normal fun-fly kind of stuff until then...
Old 08-09-2004, 09:17 AM
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Default RE: Underpowered burrito. What can I expect?

I had an ancient 46 SF on my burrito (1987 ish). It spun a 12.25x3.75 at 11300, which is weak. I could hover though, ended up swapping it with a saito, just cause it became available.

Most 40s should swing more than my crusty old 46.
Old 08-09-2004, 09:32 AM
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Default RE: Underpowered burrito. What can I expect?

I built HS-81 srevos into all my ships Tey are Te only srevo i Trustworthy. on all controls
Old 08-09-2004, 09:46 AM
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Default RE: Underpowered burrito. What can I expect?

But then again, Bosch torque rolls inches off the ground without using rudder control...... Always consider the source.
Old 08-09-2004, 09:52 AM
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Default RE: Underpowered burrito. What can I expect?

ORIGINAL: PaulSwany

But then again, Bosch torque rolls inches off the ground without using rudder control...... Always consider the source.
ROTFLMAO!
Old 08-09-2004, 10:03 AM
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Default RE: Underpowered burrito. What can I expect?

I noticed that only one fellow here is using a SAITO, and he didn't say what size. I was considering building a Burrito and using my homeless SAITO 72 in it. Is this a problem?
Thanks
Ron
Old 08-09-2004, 11:25 AM
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Default RE: Underpowered burrito. What can I expect?

Saito .72 fits perfect on the Burrito... Only prerequisite is that you like 4 bangers.....
Old 08-09-2004, 11:48 AM
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Default RE: Underpowered burrito. What can I expect?

The saito I have is a 72. Works great. I use a 13x4W apc. Its more power than needed. The old OS 46 did very well considering it wasnt very powerful.

I have an HS 81 (or 85, cant remember its the little one..) on my throttle, I am no expert on servos but it doesnt sound very sturdy. I used 625s on ailerons and 5625s on ele and rudder they sound great and are pretty quick. You dont need digis, I just bought them for the sebatana months ago and since they arent comming to the US right now, I put them in the burrito. I think I could save weight by using the non metal servos.
Old 08-09-2004, 02:45 PM
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Default RE: Underpowered burrito. What can I expect?

ORIGINAL: PaulSwany

But then again, Bosch torque rolls inches off the ground without using rudder control...... Always consider the source.
yep, then it doesn't matter what servo you use. It's only there for ground steering. Man, I wish I'd be that good. Would only use a throttle servo and yank the Burrito around with throttle input. Imagine the weight savings. Only a torque rolling free flight Burrito would beat that. Awesome [>:]
Old 08-09-2004, 03:14 PM
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Default RE: Underpowered burrito. What can I expect?

ORIGINAL: PaulSwany

But then again, Bosch torque rolls inches off the ground without using rudder control...... Always consider the source.
Oh yes.... I am aware of the amazing Bosch. Well, when you can fly your plane by telepathy you too can hover without the rudder, and even the weakest servo will fly das biggst burble sturble aeroplane wafer flyer.
Old 08-09-2004, 03:34 PM
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Default RE: Underpowered burrito. What can I expect?

Is anyone using the HS225MG servos? They're pretty light (1.1oz) and extremely fast. Rated torque is good too -- but I'm always suspicious of putting "small" servos into aircraft with large control surfaces -- especially if there's the slightest chance of experiencing flutter.
Old 08-09-2004, 03:38 PM
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Default RE: Underpowered burrito. What can I expect?

ORIGINAL: XJet

Is anyone using the HS225MG servos? They're pretty light (1.1oz) and extremely fast. Rated torque is good too -- but I'm always suspicious of putting "small" servos into aircraft with large control surfaces -- especially if there's the slightest chance of experiencing flutter.
well, I was using those, and they do strip and fail fairly easy on the fun fly planes. Centering is also the worst I have seen. They might work OK on other planes this size, but when putting through the paces they won't hold up to good. No more of these on my birds, once I am out of them (still have 3 or 4 on a beater stick). Not even on throttle.
Old 08-09-2004, 03:52 PM
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Default RE: Underpowered burrito. What can I expect?

They look aweome on paper... but the fact is the motors are weak and the pots are prone to failure.... I know a guy at our field that has replace 9 of them on one bird... the motor's just keep failing on them.
Old 08-09-2004, 05:36 PM
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Default RE: Underpowered burrito. What can I expect?

well here's my 2cents; I have a saito 72 g.k. on mine with regular old servos on 4.8 volts w/ an 81 on throttle, and it is the shizzle... standards are plenty fast enough. if worried go to 6volt. hs-225's have fragile gears. and if you put metal gears they weigh as much as a standard, so why bother? 85's have better pots than 81's but the gears are fragile, and hard to find replacements, had to go with metal gears in mine, which brought the weight up. got 322hd (resin gears) on mine, they are cheap and rugged. 425's are great servos and I have yet to wear one out, though I've broke a gearset on the rudder of my omp (don't ask!) mine is under 4 lb. w/ the 72, so with some sanding a 40 will work ok... but why not get a 75 buck s.t. 45 abc? it hovers my omp fine at 4 lb. with an 11-5. got one on my burrito winged omp at 3 lb. 15 oz w/ a macs pipe, it does fine, too.

so, use what you got, and if not enough get a s.t.45 or for a little more a t.t. pro 46, which is a great runner.

by the way, the only drawback to my burrito is it is hard to get the glow ignitor on the cylinder, as it hits the wing due to the rear angled glow plug.

and don't build hs-81's into it... and be sure to use rudder
Old 08-09-2004, 09:45 PM
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Default RE: Underpowered burrito. What can I expect?

ORIGINAL: PaulSwany

Saito .72 fits perfect on the Burrito... Only prerequisite is that you like 4 bangers.....
Come on Paul, admit it, your not as down on 4-bangers as you might act
Old 08-10-2004, 12:01 AM
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Default RE: Underpowered burrito. What can I expect?

I don't have any desire to use the HS-81 on the burrito, I was thinkin of putting the HS-81s into my heli, and then moving the HS-85MG+ from the heli into the burrito's ailerons. Or I can just use standards all around on the burrito..... Which would probably be the best bet, for both the burrito and the heli.

I plan on getting a TT .46, or maybe a magnum .46, I can hear people groaning right now, but I've had good luck with mine, and I'd buy another. Hobby people has them on sale right now, and they ship to me for free. Always a good thing. Anyways, if the burrito can fly on a .40 for a few weeks, until I can gather the cash for a better engine, I'd be set.
Old 08-10-2004, 03:21 AM
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Default RE: Underpowered burrito. What can I expect?

HS 81's are better to use on a taco, not on a 40 size airplane.
I am finishing my taco, I really hope those servo's are strong enough, they are pretty costly.

Happy flying
Old 08-10-2004, 05:24 AM
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Default RE: Underpowered burrito. What can I expect?

HS-81's strip really easy. I'd go through gear set after gear set of them on my heli. Then I got the HS-85MG+ and haven't replaced a single one in over 4 years. An HS-85MG+ costs about the same as a HS-81 and an extra gear set or two, it wouldn't take long to pay for itself.

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