The HillBilly HotRod

[Mr.HillBilly]

I was going to wait until the 2nd. round to post this here but I thought what the heck.

This is my HillBilly HotRod that I am working on.

A couple of pics over here http://hillbillyarcade.tripod.com/hillbillyhotrod/index.html Not much but I will add some more after I get her going again.


Is is a Pantera 50 with a OS 91VR-DF motor. The OS 91VR-DF motor kicks out 4.8HP at 22K so I have come up with a gear set to get me to 9.78 gear ratio. So to be at the middle of the power band I will need to pull a head speed of 2250. I have mostly been messing around with a head speed of 2100. I have kicked it up to 2250, but my current setup has some issues. I have some major constrictions going on right now on the exhaust and the intake.

Here are some vids. None of them are great flying but they are some vids. of my project. This first vid. is with the stock 8.7 gear set, it also shows you what happens when you do not set you radio up correctly (I was in a hurry). With the header and the carb. sticking out of the back if you loose the landing gear it kind of throws a wrench into the works. :YeaBaby: I forgot to set the pitch range for the Thold and I slammed it into the ground popping off the landing gear.
http://www.youtube.com/watch?v=QJGGu6-J0fo

This is the Pantera running with a 9.78 gear set, it also has a couple of flybys. I also started to run a air filter since the motor was filled with dirt. I lost a good bit of power due to that filter.
http://www.youtube.com/watch?v=I1qFJx8PGvU&feature=channel

And here is where I hit the wall on my current setup. I can keep her running good until I take the head speed up to 2250. As soon as I hit idle up 2 she leans out. There is a lot of bounce in the hover but I am over 40 feet way during these run ups.
http://www.youtube.com/watch?v=yPkzM-vefgQ&feature=channel

I had a bearing starting to go south on this last vid. so I took her down and pressed in a new bearing in the clutch bell, but I ended up messing up my mod. clutch bell. I am down until I get the new bell running.

All of my test so far have been with stuff I have had laying around the house. The pipe is for a .45 motor and the air filter is for a RC truck. Since the Pantera acts like it is going to hold up, I have started to build it right. I have a buddy going to spin me a new clutch bell so it should not be so fragile. The biggest problem I have with this is the pipe I am using, I tired to order a pipe for it but everyone is out of stock, so I am waiting on someone to get a Macs 1401, 1402, 1403, or 1404 back in stock so I can continue my project. If anyone see one of these in stock some place let me know.

So what do you guys think???

[WillJames]

:shock:

Crazy man, are you going to drag race it?

[tacoturbo]

Man, that looks totatlly insane! I friggin love it!!!! The sound that thing makes sends a chill up my spine. I bet you punch that throttle and it'll leave the skids behind. Keep up updated. Man that looks like fun.

TT

[The Dude II]

http://www.macspro.com/tunedpipes.asp


Not sure on your part #'s...don't see a listing in the above listing from macs.

Tower does have some available.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZ563&P=7

[Mr.HillBilly]

I am hoping that I can use it a Drag Bird and as a normal flying bird. With the Pantera stock you can pull 30 degs. pitch travel, if you change out a couple of parts you can even get 32 degs. or a little better pitch travel. Right now I have this bird set up for +20 and -9. Once I get it back together again I will put it on a scale, I think I am still under 9lbs. dry right now. That header I am using now is heavy, but after I get a good pipe on it and running better then I will see if I can have something made up.

If you think that thing sounds mean in videos you should see it in person, the hair on the back of you neck stands up. The wife was sick when I made these videos so as soon as I get this going again I will have some better vids. since the camera will not be stuck on a tripod.

I am hoping to get all of the bugs worked out by IRCHA, but its first public debut is going to be at Heli Smack Down next month.

[Mr.HillBilly]

Here is the pipe that I would really like to find http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNUP5&P=7 I am wanting to get this thing quieted down so I can fly it any place without issues.

It is the Macs 1404. I may give up next week and just get a muffled version but if anyone see that one avail. anyplace that is the one I would pref ere

[Mr.HillBilly]

I should have another working version here soon. My plan C guy is going to be able to make me up a bell, BUT his CNC is down right now so it will be a week or two.

I should have a 15cc tuned pipe here any day now., I found a used marine pipe on EBay. So no more bogging this motor on the exhaust side.

I was talking to JB tonight and he gave me a idea to try out also. Man it is great being able to talk to the head designer if you have a question or want some advise. :woohoo

[WillJames]

I have the pipe you are looking for I think. I will send it to you for free if you want it. I am pretty sure this is it. I have had this pipe since I was 19 and it has been laying in my plank parts box for abut 15 years unused since I crashed the plane it was on.

**EDIT - Actually, I think this is the 45 sized version of this pipe and it won't work for the .91. :DOH

http://www.helifreak.com/attachment.php?attachmentid=91439&stc=1&d=1239625086

[Mr.HillBilly]

THANKS for the offer.

My new to me pipe showed up today. This is a Macs 15cc muffled pipe. It is not my first choice but I could not pass on the price. If I still think I need this thing quieter I may order the other pipe later. I think this will get me by tho.

I held it up to see what it looked like and it will be just a couple inches short of the horizontal fin on the tail shaft.

I talked to brother in law at Easter dinner and he is not having any luck getting that clutch bell to spin true, he thinks I may have warped the bell itself when I was pressing the bearings in and out, so I gave him another clutch bell so see if he has any better luck. So one of these days I should be back up again.

Here is a shot of the old pipe and the 15cc version.

[Mr.HillBilly]

Here are a few shots of the rebuild I am doing since I am stuck waiting for the clutch bell.

The motor is mounted in the frame about where it will be when finished. As of now I have NOT been running shield over the top of the head. I may need to put a cover over the top of the head after I start to push the motor more. If you look at the motor in the half frame you can see that a new sealed duct could be constructed with out too much trouble. I have been pulling about 210F on the top of the head with no shield on earlier run-ups. Plus with the other set of frames that I was using I opened the shroud so it would take the bigger motor carbs. so I had a big cooling leak there also.

[jbeech]

I'm having trouble discerning details in the pictures of the side frame with engine. I'd advise you to photgraph this against a piece of dark gray cardboard next time.

[WillJames]

MAN that engine looks HUGE in those frames. WOW!!

[jbeech]

We routinely run from OS61SX through YS91SR engines in the Pantera. Depending on what you're doing, you may want to change the gear ratio, or add JB Weld to the autohub to reinforce it, but otherwise they're pretty reliable, and are a blast to fly. Below are some pictures.

Were's a link to one flying on our website
http://www.hobbytrading.com/audacitymodels/webvideo/P91_prototype_512k.wmv

[Garland]

Ya know Im looking at that ducted fan motor in those frames.....i say nix the mechanical fan altogether. it would raise the CG and get the carb out of danger zone between the skids.

Use a electrical fan for engine cooling and figure a way to mount the clutch with out stock fan. I dont have all the answers but if this were my baby that is what I would try.

Im also a machinist so i see difficult setups every day. this project has too much potential to stop now!

[jbeech]

Eliminating the fan is easy. Just unbolt it fomr the clutch hub. Moreover, it affects nothing when it comes to assembling the clutch stack. My reservation, however, is in adding the complexity of an electric fan, which really isn't necessary anyway because the fan is so efficient it cools that monster just fine. For folks unfamiliar with our fan design, attached is a picture. Note how beautiful the super efficient airfoiled blades are - beauty being in my eyes of course because I know what's involved in the desig.

Tooting my own horn here but this is the best cooling fan on the market bar none! Moreover, notice how we use a tapered collet on the engine side of the stack, and tapered engine nut to secure the top side of the stack. Pretty sweet, eh? I suspect this certainly isn't what you expect to find in an inexpensive 50-class model, especially since competitors use either an inexpensive to manufacture screw on hub, or in the case of a model costing three times as much (Vibe 50), they only have the collet and use a regular flat engine nut on the other side. We really think this is important and thus, took no shortcuts.

[Mr.HillBilly]

I have been thinking about moding the shroud a little more so I may have it back apart again.

I did take pics. in the house but they were too dark. When I previewed the pics on the camera they looked better so I called it good. I agree pics on a solid background would look a lot better. See how things pan out this week I may do some better pics.

I never thought of loosing the fan, but I am trying to make this as simple as possible. It would be nice to have that carb. a little more protected tho, and it does get some extra protection from the header, I may try a fan less version if this does not work out. I would need to make up another fan hub to raise the motor so the gears will still line up.

Good thought tho. Keep them coming. :thumbup:

[jbeech]

You're not going to shorten the clutch hub unless you also cut the crankshaft. There's not enough to be gained doing this in my view. Make some spacers and raise the frames from the landing gear struts by an inch, or so, to help resolve your immediate issue while you are still experimenting.

[billm]

Your pushing JB's design. I like that.
Let me know when your going to fire the beast up so I can hide under the bench.
good luck my friend.

[Mr.HillBilly]

Oh I ante pushing it yet. I might start to put a litle stress on her since I have the right size pipe now. :YeaBaby:

I have 2 different people working on a clutch bell, I am hoping one of them gets me going here soon. I am going to be a little nicer to this bell pressing in bearings. As soon I have a CNCed version I can be mean to it again.

I decided I am going to do a quick mod. to the frames so I can add a shroud to it. I just have the frame together and the servos mounted so it will not take much to break it back down again. I figure I might kick myself if I start to have some heat problems down the road and it could have only taken me 10mins. to tear it back down instead of having it flying then needing to take it back down again.

[billm]

if you need any help getting drawings to your machine head. I have AutoCad and SolidWorks 2009. Use them high faluten tools every day.

[Mr.HillBilly]

Well here is what I came up with to help on the cooling side some if need be. I never had any problems keeping it cool with the stock setup but with summer around the corner and this new pipe I may have some issues when I start to push it hard. I made up a new shroud and dremeled out part of the old one in the stock frames. The way it looks right now it should never slide up or down since it is cut out for the frame on the lower side and then it wraps around part of a cross post at the top by the clutch. I may need to trim the top part if it is too close to the clutch bell.

If you want to see really close up pics. I have them posted at http://hillbillyarcade.tripod.com/hillbillyhotrod/id3.html

[jbeech]

The goal with air flow is to maximize contact with the engine's cooling fins. Consequently, any gaps between the shroud and engine should be minimized so as to reduce air leaking out from around the engine.

What's more, you want to actually force the air through the fins and thus, for example, the 1/4" gap between the top of the cylnder head and the shroud material in your picture is something you might want to reconsider. Remember, cutting the shroud back from the engine more than about a 1/16" from the head - for working clearance - as I've done in the YS91SR installation pictured below, is best.

Realistically, the only two practical improvement you can make are to:

a) On the carburetor-side of the shroud: add a piece to fill the gap in the shroud surface where the carb normally goes - to prevent air leakage. I used a piece of bright-green tape for one example of the size and shape of material, perhaps a piece of plastic from a playing card. I've also used Photoshop to show what it might look like if we had planned for an RI engine in the first place, e.g. with plastic.

b) On the head-side of the shroud: perhaps you may wish to add a piece of stock as well, but don't bother unless it actually overheats. In my YS91SR install below it doesn't overheat. I used a piece of masking tape to simulate what I am thinking of. Moreover, if your engine's head sits proud of the shroud, just shim it outward 1/8" or whatever at the edges.

Attach these is as easy as shoogoo, or with tiny screws similar to how the windscreen is attached to the canopy. Moreover, this isn't so critical you couldn't just screw individual halves to each side frame and let them butt together, or even overlap if the material is nice and thin, upon assembly of the frame halves instead of using a single piece of fill material.

My 2¢

[billm]

Nice call JB.
The only other thing I could offer is to add A/C and a remote trunk release.

[The Dude II]

:rolling

[jbeech]

I spoke with John (Mr. HillBilly) and he can easily move the shroud material to more closely contact the head. Moreover, addressing his concern of the material melting, I told him not to worry if it melts slightly as it will only be a local occurence anyway, e.g. it will only melt enough to provide clearance. What's more, he's also going to add small pieces of fill material at the sides of the head to better force the air flow through the head area. He's a fast learner, i.e. a pretty good dinkum tinkum in my view, and this is a most interesting project.