Herc Pilot

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Just curious if anyone has built, flown, or seen this plane. Was thinking about it with a pair of O.S. 26's and wondered if there is enough room in the cowls for the engines, how it flies, any problems etc. Searched the archives but didn't come up with anything.

http://www.nitroplanes.com/elbrgasovbrt.html

FallDownGoBoom

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Never seen or heard of the plane, but as for fitting a pair of 25's in the cowls...

My Uravitch 52.5" wingspan Bronco had ABS cowls over a pair of TT 25's. If mounted vertically, there was a problem with the mufflers clearing the wing (see the Bronco 3-blade prop size thread for the way one guy solved that problem). I mounted my 25's horizontally, and used muffler extensions to clear the bottom of the booms. If you rotate the engines further (around 120 degrees), then the mufflers can be lined up on the centerline of the booms, but you end up with your glow plug below your fuel source. Don't know of anybody that's mounted the engines inverted.

In all cases, one had to cut holes in the cowls for the cylinder head, carb opening, etc. Since thie plane you're asking about has a 48" wing span, the booms are are probably even narrower than on the Uravitch model, which would mean some serious surgery on the cowls. One solution I saw was to mount the engines about 45 degrees off vertical, and then just cut an entire side of the cowl away.

Might be better to power this one with electrons if you're concerned about appearance.

Herc Pilot

My Feedback: (15)

Thanks FallDownGoBoom. I was not terribly concerned with looks because I was considering this plane as sort of a test plane to break in four 26's that I bought for a C-130. I wanted to make sure they were dependable before putting them on something with a lot of build time in it. Problem is, on the C-130 my engines are mounted inverted with onboard glow and it didn't look like there would be enough room in the Bronco to go that route. So, now I'm not sure if I should mount them the same as I intend to do in the 130 or if I should mount them otherwise just to get them in the air, broken in, and dependable. Sent a mail to Nitro Models asking about room in the cowls. Even if they end up getting mounted upright it would be a good way to break them in. Maybe I should just scrap the Bronco idea and go with something more simple like a Twinstar, but the OV-10 is a lot better on the eyes. Thanks for your input and I'll finish reading through the prop size thread for more ideas.

Wayne22

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I'd think the Hobby Hanger OV-10 might be a better fit for the 26's.....I have a twinstar with a brace of them, and it flies just fine!

rryman

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Or you could just break them in on a test stand and try them that way. I broke in all my .25's for my 130 on a test stand and then mounted them. Of course, mine aren't inverted, but you could mount yours that way on a test stand to check the reliability out.
Randy

FallDownGoBoom

My Feedback: (1)

I'd agree with Randy, if all you want to do is break-in the engines, then a test stand is much cheaper than a Bronco... unless the plan is to strip out all the servo's and Y-connectors for use in the C-130 after you're done. My TT .25's ran fine in the air after a couple of tanks of fuel on the test stand... and it was easier to tweak the idle settings. If looks aren't a big concern, just leave the cowls off.

I would also think the Nitro OV-10, if it really only weighs 4 lbs, would be a real hotrod with a pair of 25's. The Uravitch Bronco's come in around 6 to 8 pounds, and (once I got it off the groud), mine would move out pretty well. I cruised it around 50/60 % of throttle quite comfortably. Several of the Uravitch Bronco's have had their wingspans increased to around 60 inches to reduce the wing loading. If the Nitro spans 48" x (I'm guessing) 9" and weighs around 5 lbs with the OS engines, I think that works out to around 27oz/sq-ft. Not too high, but I'd think landing speeds might get real interesting.

rryman

My Feedback: (2)

Just for the record, one thing I'm doing on my Herk is running low pitch props and keeping the idle rpm high enough that I don't have to worry about a flame out at reduced power. I believe mine runs about 5k at idle, but still won't move on grass. The higher rpm also give it more of a turbine sound when taxiing.
Randy

Herc Pilot

My Feedback: (15)

Thanks everyone for the great advise.

Now to get way off topic, a little back story on the Herc. It's roughly 100" span and was built scratch from plans. It's been so long I can't even remember what plans they were, but know they came from a model magazine. It's similar in size to Skip Mast's. I built it 7 or 8 years ago and had 4 Royal .28's in it (way too overpowered). Mounted inverted with glow they still weren't reliable enough for me to trust them and had to keep the idle way up to keep one of them from dropping out. At the increased idle, it was more like a race car than a Herc and in no way dependable. Even the on board glow didn't help. I'm not sure what I was even thinking mounting them inverted in the first place other than just trying to keep it looking scale, but proved to ba a pain. I sold off the engines and let it sit in the hangar for a long time. I'm back into the hobby pretty heavy again after only sport flying for a while and decided it was time to fly this sucker and give it another shot with the engines.

I just found a deal on the 26's from someone here on RCU and always thought small 4 strokes would be the perfect fit for the plane. I grew up being taught to "just break 'em in in the air". More I think about it, bench running them mounted the same as in the plane may be the smartest way to go. All my extensions and servos and everything are still in the plane, so wouldn't be switching all that out in another plane such as the Bronco, just thought it would be a fun way to break the engines in and to learn their traits.

falldown - I'll give the Uravitch Bronco a look, but after listening to all your suggestions about bench running, I think I am leaning more to that route than having to buy all new gear for a test plane. You bring up good points.

rryman - Great idea about the props. I'm sure using that logic will keep my plane from trying to run away from me at idle on the ground.

Sorry so long winded, but thanks for all the good info and keep it coming.