My first Housefly Mod - RC Groups
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Jan 17, 2002, 06:50 AM
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jk's Avatar

My first Housefly Mod

since i didn't care too much for the cardboard boom in my Housefly kit, i decided to use a 5mm CF boom (woven Breeze tubing) with a tight slip fit so that i'll be able to later experiment with different boom lengths and configurations rather than gluing it in. this way i could even try a Piccolo boom since on the piccolo the motor is adjustable to enable changing pinion sizes/ratios. (i also have some custom made, ultralightweight CF tail rotor blades that fit the piccolo's system that i use on the Moth)

in order to make the boom replaceable,i needed a smaller diameter hole in the undercarriage to insert an aluminum sleeve to hold the smaller boom in place, so i just made some new "A" supports from 1/32" balsa covered on both sides with .008" CF plate. the new braces are a little stiffer & stronger but weigh exactly the same as the original plywood ones but the CF boom is lighter than the cardboard boom by 1.2 grams.

here's a picture of the front brace which is actually .25 grams lighter than the stock one:

the landing struts go into the balsa, between the two CF plates.

i'm going to use the stock ply top plate since it's easily strong and light enough as is and it's cut very precise for the motor and mast. Here's a three more views of the chassis (of which the wood will be later blackened with a black sharpie- as painting it would only add more weight)
front view:

rear view, showing the aluminum sleeve to mount the boom (the rear brace is .25 gram heavier than the stock one, due to the aluminum sleeve).

and finally, the side view:

so far, i like this little bird.the chassis complete with boom as shown weighs only 6.2 grams. i purchased the recommended GWS pico servos for it (but now i'll just use them in something else)and decided to go with Hitec HS-50's instead, since they're a little lighter and draw less current. i'm also going to replace their wires with an even smaller gauge to lighten them even further.

hopefully it'll be airborn by the weekend.
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Jan 17, 2002, 10:48 AM
FPV really is fun.
Scotth72's Avatar
Looks great, John. I am waiting on parts, and I will try to get mine in the air as well.
Jan 17, 2002, 10:50 AM
Registered User
I'm super jealous that:

1) you have your HouseFly kit already.
2) you have the ingenuity and skill to do such cool things with it already!
Jan 17, 2002, 12:00 PM
Registered User
Hi John. How much do your HS-50's weigh? According to the specs I have, the HS-50 weighs 5.8g and the GWS Pico weighs 5.4g.
Jan 17, 2002, 12:39 PM
Registered User
Looks great as usual. I was wondering why the kit didn't have a CF boom in the first place. Seems like the HF would benefit from CF throughout. Cost was probably an issue. The cost is very respectable for what you get.

If you keep this stuff up you I am going to have to get one of these little guys.

Please stop

Jan 17, 2002, 01:15 PM
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jk's Avatar
thanks guys.
okay, here's the scoop on the tiny servos:

the hs 50 weighs in in at the lightest and draws the least sappears that some manufacturers post the servos's weigh w/o the control leads (which i find to be very misleading). i read on the GWS site that the GWS Pico servo comes with one BB but upon inpection found out that it does NOT. and the Cirrus CS-10BB is the same exact GWS servo, but it does contaim a BB on the output instead of a nylon bushing. the CS-10BB seems to have the least play or slop of all of them, but i never had a problem with HS-50's and since it draws about half the current of the other two, i chose to use them in the housefly.

here's the weights w/o a servo horn or mounting screw, but with the control wire as it comes right out of the box. the HS-50 does have the shortest control wire, but it's a larger gauge than the other two.

HS-50= 5.85 grams
GWS Pico servo= 6.00 grams
Cirrus CS-10BB= 6.3 grams

BTW,when you cut off the mounting ears, the GWS pico and the HS-50 will weigh the same (the GWS's ears are thicker)
Jan 17, 2002, 05:48 PM
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jk's Avatar
i just talked on the phone to Mario and Walt today. Mario designed the heli (Housefly) around the GWS pico servos since they are so small-they fit better. and Walt was saying to basically use whatever is the lightest, since the current draw difference will be neglible in a 3-10 minute flight anyway. so after i shorten the leads and use the 32 gauge wire, i think the PIco's will be just fine.

Walt also did some quick, rough estimate calculations for me and figured that it'll take about 26.7 watts (pulling 2.8 amps) to lift this little heli. if the GWS motor that comes with the kit is efficient putting out that amount of power, he figures that we might be able to get up to 7 minutes of hovering flight time using seven 370 mah cells. i have a couple of 180 motors that Mario also suggested that i might try and if the GWS can't put out that much power, i'm pretty certain that the 180 can.

we'll see what happens this weekend (or even possibly as early as friday night). i'm getting more and more optimistic about this heli as i continue to build it up.
Last edited by jk; Jan 17, 2002 at 05:55 PM.
Jan 17, 2002, 05:55 PM
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scmodchips1's Avatar
John - The housefly can lift alot of weight, but due to no mixing on the tail it will want to piro on you. I tried one of my 100 gram 8-cell nimh powerex packs last night, and the housefly shot up to the ceiling and went into an uncontrollable piro. I'm am trying to setup my Housefly with a Focus 4 radio since I want to see how it performs without any mixing. I was tempted to just set it up on my 8uhfs with mixing, but as Mario advertised, it is supposed to work with the basic 4 channel radio.

Regards - Steve
Jan 17, 2002, 05:59 PM
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scmodchips1's Avatar
I almost forgot to mention that I just bought a 7-cell 150mah nicad pack 1/3AA, so I'll have to test that out and see if the torque reduces enough to where it doesn't want to piro uncontrollably. I'll have to play with the pitch on the blades.

Jan 18, 2002, 04:10 PM
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what were to happen if u did have mixing?
Jan 18, 2002, 04:27 PM
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scmodchips1's Avatar
It would be alot easier to maintain the tail position when giving throttle inputs because the tail rpm would change with respect to the throttle. I probably would not piro involuntarily like I did. I did test the housefly with the 7-cell 150mah pack last night, and the tail was pretty solid since there was less torque due to the lighter overall weight of the heli as opposed to the large 8-cell 650mah pack I tried out for kicks

Regards - Steve
Jan 18, 2002, 04:56 PM
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Peter W's Avatar
What IS this housefly thing?
What does it look like?
I gather it's a heli but is it smaller than the piccolo? I think the piccolo is still too large to fly comfortably in home, can't a heli be made say15 cm long?

Jan 18, 2002, 05:51 PM
Just an average RC'er
Jim McPherson's Avatar
Nice looking work there with the carbon. Did you have an opportunity to try the cardboard boom in the housefly. I was absoultly apauled at the idea of a cardboard boom at first, however after using it, and replacing it (yes already) I found that it works alot better than I thought it would. However I don't think we'll ever have to replace a carbon one since unlike the hornet a boom strike wont do anything.
Jan 18, 2002, 07:25 PM
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jk's Avatar
i haven't even flown mine yet (so i didn't try the cardboard boom). i just went to the CF one so i could try dirfferent booms on it and it's a little lighter that the stock one. since it's only 7" i think it'll never break unless i do something really stupid.
i aim to have it fliying late tonight (if my G/F lets me work on it.
Jan 18, 2002, 07:37 PM
misskimo's Avatar


I never heard of a heli by the name of G/F