OM21 build

[Doug Smock]

ok, well i think i might have found the problem....when i rotate the shaft freely in the tube (without the couplerattached and no prop) it feels like there might be a very slight bend in it that could cause the vibrations when spun faster.....

Maybe that's it!!! It has to be something, it can't be nothing. LOL

Doug
PS On your next straight shaft build, opt for a shaft with bushings in it.

[saleens7]

i dont think ill ever use a strait shaft again....although im considering rebuilding this boat in the future using a brushless motor and a flex shaft...probably a .098" one....

[hookedup]

shaft

i got a used OM21 hull off of RRR, i put a 19 turn motor in it and 6 cells and was pretty disappointed it was way slower than my SV. i am going to go brushless and lipo. i have been told the OM21 hull can go 40+ mph easy, so we'll see.

[saleens7]

yeah, mine wasnt exactly speedy either....at one point when the shaft didnt vibrate and i used the high rpm motor with the 31mm prop it was doing about 20mph....although it overheated alot and was almost uncontrollable....

im already looking at some cheap lipos at maxamps...ill get two lower mAh 2s lipos (like 2-3000mah) and wire them in parallel....im looking at a feigao 8s for the motor....ill be happy if i can get in the high 20's to low 30's with this hull...if its going to go 40+ it will probably have to be a little weighed down or else it might be too hard to control.....

although that might have to wait till later....once i get the SW36 and SV27 finished im going to save up and buy some new forks for my bike...then im looking into buying an rc car.....although im still not so sure i will buy one yet....i am looking into the red cat racing volcano....pretty cheap for a nitro truck....there is also the nitro pede and electric pede (not the VXL version...way too much $ for the likes of me)....and for christmas im going to be buying some stuff for the drifter..(probably motors, esc's, and motor mounts)....i might be able to get the OM21 hull and hardware in there as well....but i would rather wait until i have no more projects before i do that.....much easier to build/fund when you dont have to buy parts for other projects....

[SJFE]

Hey ya know that I thought was pretty kewl (car wise). That HPI E-Savage with the buggy body. It looks really fun. I think thay claim 25 mph out of the box & it comes with 2 packs and a charger. It's just somthing I allways look it in the mags and wonder "what if". While we are talking about other areas of rc..I think MrsSjfe is gettin me an Efligh Bade CX2 for christmass :p. My little picoo z is getting tired. I think the lipo is almost shot.

[saleens7]

yeah, the e savage does look nice...its the 350$ price tag thats driving me away....

the nitro pede is the most money im willing to spend for a first rc car (260$)...

although im really liking the volcano SV......18 motor stock, 4WD, 30+mph stock, stable (the pede like to flip alot) and only for 220$....ive taked with people who have it and its a pretty good truck....although the traxxas is known for its durability and i think it does like 35-40mph stock....there are also many aftermarket parts for it....its just the price, lack of stability, and being 2wd thats keeping me from buying it.....

although with all of these things i need to buy, i dont know if ill be able to start on the OM21 until next year....and even then when i get a job, almost all the $ i make will be going to savings for a car and college expenses....

[SJFE]

One thing to consider with buying off brand cars & truck is parts avalability. i always looked @ the cheaper units but was worried about replacing broken stuff & upgrades.

[Ocean Racer]

I have a RTR XTM ep Excellerator 2wd its a nice car it does about 10-15 mph stock at hobby ppl its 150 bucks its a 1/10th scale. i spent around a 110 bucks and ugraded i got a new esc and modified motor. I got a Xtra Quake no turn limit esc $80 and a Method R 17x2 turn modified $20 according to them if i get a higher powered batt i can do 35mph. But im going around the mid twenty's and thats on a 6cell 1500mah Ni-Cd it comes with fully threaded shocks adjustable slipper clutch servo saver u can adjust the tires tow and tilt its a fun car to drive on or offroad.:D

[Rex R]

20-25mph is about right for the om21 with a 19T and a 31mm prop. and yes things will get hot if the boat isn't set-up right.

[FRED]

om 21 build

REX is straight on the button for equipment and speed and prop. Someone mentioned sv-27 comparing to om-21. No way JOSE! I was going to buy a om-21 but i would spray 3m-77 inside and the lay fibercloth on top of 77 and push in at cranies and noaks and let try. The hull may have alittle give but will be real tower of strenght. Now for a motor, a handwound 14/2 motor with .130 flex and teflon and cg at 30% and carbon fiber 631 and lipo 3850 mah, this would be a long lasting unit with hardly any maintenance. Oh yes, i would polish my flex till it shines with very little ribs to the touch and a lit touch of teflon grease. Also homemade hardware! Forgot a setup. Motor Maxx wild on 8 cells with a carbon fiber 633 or a lipo 3s-11.1 and water cooled.I have this setup in a No Step 1 and it flies for 5 minutes, good enough for me!

[Rex R]

while I don't have direct hands on experience building etc an om21...I do know my electrified is on a par with the ones I've run with (roughly 21-24 mph 19t spec class). the key for keeping these boats cool is to 'air out the hull', about a 1/4" above the water riding the prop. can be a wild ride if your turn fin gets bent :)

[FRED]

om21

Rex, i had 2 Electrafieds with a Chameleon #2110 which had a higher rpm and a 534 prop but one bad point was the turn radius which was too long. One day some geese flew in and landed right in front of the boat. I veered and hit a water sprayer and i kept on the throttle and pushed it around enough to get it home and it was on plane, one tough boat. Right now am working on Randy Naylor Patriot little boat with a 480 speed with 1200 lipo and a carbon fiber 629. Wooden 22" boats i make seem to turn out the best of the bunch. Oops better not hijack om21 posting, sorry , carried away!

[FRED]

om21

Saleens 7, you were running a solid shaft in the om21! I thought they were stuffing tube and .130 flex and a carbon fiber 631 and a Chameleon motor. You know what your doing and when i read where you found shaft was bent, i'd keep using the shaft since you have it already setup for the shaft. Let everybody know how things turn out. Tower has a motor called Speed Secret at 40,000 for $22.00 and best is to put good non-groove brushes in upright and let it fly. Watercool and hood cool too. I have one in each Mutineer with a carbon fiber 631 prop and you can't catch them, nope, retired here and i have 2 or 3 spares of the secret if needed. I don't pass out bull cause i like to see boaters have as much fun as i do! I'm retiring from thread as i have no further info, thanks!