stunthanger.com
General control line discussion => Open Forum => Topic started by: Robert Zambelli on February 12, 2010, 07:07:17 AM
-
I will install it in the Red Hot Angel for evaluation.
For information and availability, contact Brodak Mfg.
If anyone is interested, I will post more details.
Bob Z.
Roger V. - here's the engine for your RHA!!!!!
-
Why do they keep putting on those huge expansion chambers, which everyone just changes to tongues?
Any pricing info?
Does the fact I asked mean I can't afford it as with yachts and trophy wives?
-
A new .15?? Good news, I guess............
Another bit of good news would be "A large shipment of B 40's is in stock"!! ;D Any chance of that, Bob?
Cheers,
Jim
-
BOB
now we need john to come out with the 46 and 60 Brodak engines I would love to test them out. keep me updated on the 15 thanks for helping out judging at the KOI
THANKS TOM WEEDMAN
-
How about some engineering details?
Bearings?
AAC?
ABC?
Etc.
Bill Lee
-
Cool, good to see what should be a good .15 on the market to replace the discontinued O.S. LA-S. I have to agree with the muffler comment, all the manufacturers should take note from Horizon on that point and just supply a tongue muffler option from the get go.
Now, if a person can actually get the engines... ;)
-
How about some engineering details?
Bearings?
AAC?
ABC?
Etc.
Bill Lee
Also curious as to the manufacturer.
-
OK, here are a few details.
First off, it's a miniature of the 40 and 25, made by the same company.
Piston/liner is AAC.
The bearing appears to be cast in and features an oil groove as shown.
4-bolt head with aluminum shim, mild hemi with a .070 wide squish band
Bore .572, Stroke .582.
Standard collet type NVA.
Warbird wrote: "Now, if a person can actually get the engines... ". Call Brodak and you might just get a pleasant surprise!!!!
I will mention the muffler comments to John.
Bob Z.
-
OK, here are a few details.
First off, it's a miniature of the 40 and 25, made by the same company.
Piston/liner is AAC.
The bearing appears to be cast in and features an oil groove as shown.
4-bolt head with aluminum shim, mild hemi with a .070 wide squish band
Bore .572, Stroke .582.
Standard collet type NVA.
Warbird wrote: "Now, if a person can actually get the engines... ". Call Brodak and you might just get a pleasant surprise!!!!
I will mention the muffler comments to John.
Bob Z.
Cool!
And we know the bushing is some type of aluminum alloy (see the B25 question!).
How about the weight without muffler? I am curious how it compares to the Fp15 and FP10 and how well it will go with the "jr" planes.
-
Cool, good to see what should be a good .15 on the market to replace the discontinued O.S. LA-S. I have to agree with the muffler comment, all the manufacturers should take note from Horizon on that point and just supply a tongue muffler option from the get go.
I guess I don't understand the problem, or why everybody just immediately tosses the muffler. In just about every experiment I have tried with these sorts of smallish schneurle engines, they ran better, or even much better, with the stock muffler. It's the key to the 20FP run, for example. It runs very poorly with a tongue muffler or open exhaust. A few ounces is never worth even a slight reduction in the run quality.
I have no idea if this is the case for this new engine, maybe it would work better with a different muffler, or maybe (like all the others I tried) it would screw it up. But for goodness sake, don't let this sort of "fencepost wisdom" folklore overly effect the results. It would be a real shame if manufacturers started putting out engines that ran more poorly and more noisily than they should just because someone has it in their heads that it can't possibly be right without ever having tried it.
Brett
-
What Brett wrote does indeed make sense especially when we understand the entire muffling principle.
A large part of the muffling comes from allowing the (hot) gases to expand, thus dissipating energy. Obviously, a tube muffler will accomplish this.
Regarding a tongue muffler, there is minimal volume and therefore minimal energy is dissipated. I have seen more than a few people employ these with noticeable loss in power. This is mainly due to having a small number of hole or the holes themselves being just to small. Too much back pressure. Yes, they muffle but at a cost.
I have tongue mufflers on two Fox 35s and in order to get decent power, I had to open the holes to where there was minimal muffling.
Anyhow, I weighed the B-15. It is 4.6 ounces. The muffler adds 1.0 ounce.
The LA-15 weighs 4.3 ounces.
I attribute the weight difference to the B-15 having a 1/4-28 crank thread and an aluminum backplate.
The LA has a 5 MM thread and a plastic backplate.
The B-15 case is .10 inch wider where it fits between the beams.
The B-15 is physically a bit larger.
The mounting hole spacing is not the same.
Bob Z.
-
Cool!
And we know the bushing is some type of aluminum alloy (see the B25 question!).
Is the bushing "Babbitt" ?
ie- White metal
-
Hi, Douglas. It's possible but I don't think so. The are around six ASTM grades of Babbitt in common use today but they tend to be used mostly in large, slower sliding speed applications. They tend to be avoided where high precision is required, as in our engine fits. Most of them are different percentages of tin and antimony as well as some containing copper and lead.
Many of the modern high speed bushings in use today are manganese/bronze, silicon/aluminum/bronze or similar formulations.
Before he died, I was working with George Aldrich on retrofitting Fox 35 cases with manganese/bronze bushings. I have had very good results with the retrofit and have also done McCoy Red Head cases. Manganese/bronze is often found in exotic engines, used as valve guides.
Bob Z.
-
Seems funny, if this engine comes from the same manufacture that makes the .25 and the .40 why cant they make a run of .40's
-
Tom - have you called Brodaks to see if there are any 40s in stock?
Bob Z.
-
Good advice from Bob- ask me how I know.
-
I guess I don't understand the problem, or why everybody just immediately tosses the muffler. In just about every experiment I have tried with these sorts of smallish schneurle engines, they ran better, or even much better, with the stock muffler. It's the key to the 20FP run, for example. It runs very poorly with a tongue muffler or open exhaust. A few ounces is never worth even a slight reduction in the run quality.
I have no idea if this is the case for this new engine, maybe it would work better with a different muffler, or maybe (like all the others I tried) it would screw it up. But for goodness sake, don't let this sort of "fencepost wisdom" folklore overly effect the results. It would be a real shame if manufacturers started putting out engines that ran more poorly and more noisily than they should just because someone has it in their heads that it can't possibly be right without ever having tried it.
Brett
Well the reason I ask is that most of the "old standard" 15 size planes are overwhelmed by the weight of the standard 15 sized engines--even before you add a muffler. Add the muffler (and I recommend some type of muffling with a 15 sized engine) and now you need a lot of tailweight.
You don't see this problem with the 20-25 sized engines, because (usually) they seem to be going into "old standard" 35 sized plane, so even if they end up a little heavier than a Fox 35, you won't need to add a lot of extra tailweight (if any).
For me that is the issue. I've used 10 sized engines on the 15 size planes, simply for balance and weight reasons--- and in additionthey have plenty of power too. I've also used a Fox15BB (a heavy 15) with stock muffler on a FliteStreak Arf.
So as a comment, the real issue I guess, is that the "Jr" planes, typically are on the small size for a modern 15 size engine. Maybe we need some new designs which fit the power you get from a modern powerplant.
-
Brodak's website as of 5 minutes ago, "Brodak .40" On backorder"
-
Tom - CALL (telephone, not e-mail) Brodak. Talk to John and ask him directly.
For the moment, forget the website.
Bob Z.
-
Well the reason I ask is that most of the "old standard" 15 size planes are overwhelmed by the weight of the standard 15 sized engines--even before you add a muffler. Add the muffler (and I recommend some type of muffling with a 15 sized engine) and now you need a lot of tailweight.
If memory serves, Brodak was considering producing the Full-fuselage Peacemaker some years ago. That should be a good match.
So would the profile Peacemaker for that matter.
George
-
If memory serves, Brodak was considering producing the Full-fuselage Peacemaker some years ago. That should be a good match.
So would the profile Peacemaker for that matter.
George
I've got the MAN plans for the full fuse Peacemaker--looking at them right now.
It definitely smaller than the FliteStreak, and bigger than FS Jr----closer to the "full size" FS I think.
Even tho' George built it for the Oliver Tiger 15 Diesel, I think you would need to really use light wood for a 15. But like I said, I fly the "full size" FS Arf with a Fox15--with a 7-4 prop turning a pretty penny, and that is a ball. But that ARF is really light--I am not sure I can build that light!
-
I will install it in the Red Hot Angel for evaluation.
For information and availability, contact Brodak Mfg.
If anyone is interested, I will post more details.
Bob Z.
Roger V. - here's the engine for your RHA!!!!!
Great idea, Thanks Bob, H^^
Roger