Would a By-pass like this hold the turbine well?
08-12-2010, 12:22 PM
#1
Would a By-pass like this hold the turbine well?
Hey All, look at these photos, they are from my Fei Bao MB339. Installing a JR Rhino in there. The turbine "bolt-down" straps are not very wide and do not reach the mounting rails pre-installed by manufacturer.
Usually, I would just attach 2 scrap rectangular 2" X 4" pieces of plywood to the rails on each side and make the gap between the rails narrower so the turbine would mount to the new narrower "rails", but as it sits like this the turbine is the perfect height with respect to pipe and bypass. if I were to use any reasonably safe thickness of plywood to make the new rails, that would make the turbine sit higher and therefore cause other problems-it would not be aligned with pipe anymore.
I have 2 good options as I see it:
1. Mount By-pass to rails since the bypass is wide enough, then mount turbine to bypass by drilling holes into bypass and using bolts or screws to hold in place -this is sort of way BVM does it I think, but I am unsure if this is a BVM bypass and if it presents safety and structural integrity issues should bypass melt/break, etc... during flight.
2. mount plywood scrap plates to rails, make rails narrower and then mount turbine to new rails, and then I have no idea what to do to compensate for turbine sitting higher other than moving pipe up or pointing turbine nozzle down and I think that would cause its own set of issues since now I am changing angle of thrust, etc....
What you guys think? I would appreciate creative answers dealing with this specific solution/problem.
Thanks everyone in advance,
Shaz
Usually, I would just attach 2 scrap rectangular 2" X 4" pieces of plywood to the rails on each side and make the gap between the rails narrower so the turbine would mount to the new narrower "rails", but as it sits like this the turbine is the perfect height with respect to pipe and bypass. if I were to use any reasonably safe thickness of plywood to make the new rails, that would make the turbine sit higher and therefore cause other problems-it would not be aligned with pipe anymore.
I have 2 good options as I see it:
1. Mount By-pass to rails since the bypass is wide enough, then mount turbine to bypass by drilling holes into bypass and using bolts or screws to hold in place -this is sort of way BVM does it I think, but I am unsure if this is a BVM bypass and if it presents safety and structural integrity issues should bypass melt/break, etc... during flight.
2. mount plywood scrap plates to rails, make rails narrower and then mount turbine to new rails, and then I have no idea what to do to compensate for turbine sitting higher other than moving pipe up or pointing turbine nozzle down and I think that would cause its own set of issues since now I am changing angle of thrust, etc....
What you guys think? I would appreciate creative answers dealing with this specific solution/problem.
Thanks everyone in advance,
Shaz
08-12-2010, 12:42 PM
#3
RE: Would a By-pass like this hold the turbine well?
Hi Shaz.
Here is my 2c.
1. If you wanna go for this option, you need to glue a 2 mm real carbon fiber plate at the back of the bypass mounting tab. This plate shall be as wide and long as the flange to be able to retain the engine efforts.
2. Plywood is a good option as well but as you mentioned, you'll be offsetting the turbine to the top a bit more. You will need a good quality aviation plywood of at least 3 mm. Then you can use aluminium ( 2,5 ish mm ) as Gary said.
IN NO WAY you should simply bolt the engine to the bypass glass fiber. Or your engine will soon depart from the aircraft with the consequences that you can imagine...
Also do not put the bypass top cover on this setup as you will certainly choke the engine. The bypass is too narrow for your setup. I would also recommend you to slightly move the engine aft so that the air can pass between the front of the engine casing and the bypass intake.
Here is my 2c.
1. If you wanna go for this option, you need to glue a 2 mm real carbon fiber plate at the back of the bypass mounting tab. This plate shall be as wide and long as the flange to be able to retain the engine efforts.
2. Plywood is a good option as well but as you mentioned, you'll be offsetting the turbine to the top a bit more. You will need a good quality aviation plywood of at least 3 mm. Then you can use aluminium ( 2,5 ish mm ) as Gary said.
IN NO WAY you should simply bolt the engine to the bypass glass fiber. Or your engine will soon depart from the aircraft with the consequences that you can imagine...
Also do not put the bypass top cover on this setup as you will certainly choke the engine. The bypass is too narrow for your setup. I would also recommend you to slightly move the engine aft so that the air can pass between the front of the engine casing and the bypass intake.
08-12-2010, 12:43 PM
#4
RE: Would a By-pass like this hold the turbine well?
Unless the bypass is very thick walled with thick flanges, I would not trust bolting the turbine to the bypass only. Personally, I would epoxy ( or maybe bolt) a 1/4" piece of aircraft grade plywood full width to the bottom of the existing rails and let that ply extend out to the bypass. I would then cap that plywood with another piece of aircraft ply that is thick enough to flush it with the topside of the existing rails. By this method, no change is made in reference to the height of the turbine.
08-12-2010, 01:48 PM
#5
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RE: Would a By-pass like this hold the turbine well?
1. Mount By-pass to rails since the bypass is wide enough, then mount turbine to bypass by drilling holes into bypass and using bolts or screws to hold in place -this is sort of way BVM does it I think, but I am unsure if this is a BVM bypass and if it presents safety and structural integrity issues should bypass melt/break, etc... during flight. From the looks of your bypass, it is not a BVM bypass tube.
In the photos your mounting flanges appear to be parallel to the engine mount plates in the airframe, and appear to be three or four inches long.
BVM bypass tubes feature angled mounting tabs designed to use the BVM cast aluminum tees that come with our engine mount strap kits. For this reason, the mounting tabs shown are 1 1/2" long. You will also find Kevlar joining tape at each end of the tube opening.
BVM recommends using the bypass tube cover in our installations.
For contrast, the accompanying photos show a P-200 sized BVM tube for the Ultra Bandit, and a P-70 sized tube for a BVM T-33.
Note how the engine is mounted in the large tube. There is 1/4" plywood under the fiberglass ears, and we use 4-40 hardware.
Do you know of any reason you could not use this type of mount strap and tees on your engine? What is you engine case diameter?
BVM has mount straps available in various sizes to fit various engines.
In the photos your mounting flanges appear to be parallel to the engine mount plates in the airframe, and appear to be three or four inches long.
BVM bypass tubes feature angled mounting tabs designed to use the BVM cast aluminum tees that come with our engine mount strap kits. For this reason, the mounting tabs shown are 1 1/2" long. You will also find Kevlar joining tape at each end of the tube opening.
BVM recommends using the bypass tube cover in our installations.
For contrast, the accompanying photos show a P-200 sized BVM tube for the Ultra Bandit, and a P-70 sized tube for a BVM T-33.
Note how the engine is mounted in the large tube. There is 1/4" plywood under the fiberglass ears, and we use 4-40 hardware.
Do you know of any reason you could not use this type of mount strap and tees on your engine? What is you engine case diameter?
BVM has mount straps available in various sizes to fit various engines.
08-12-2010, 02:15 PM
#6
RE: Would a By-pass like this hold the turbine well?
ORIGINAL: Harley Condra
1. Mount By-pass to rails since the bypass is wide enough, then mount turbine to bypass by drilling holes into bypass and using bolts or screws to hold in place -this is sort of way BVM does it I think, but I am unsure if this is a BVM bypass and if it presents safety and structural integrity issues should bypass melt/break, etc... during flight. From the looks of your bypass, it is not a BVM bypass tube.
In the photos your mounting flanges appear to be parallel to the engine mount plates in the airframe, and appear to be three or four inches long.
BVM bypass tubes feature angled mounting tabs designed to use the BVM cast aluminum tees that come with our engine mount strap kits. For this reason, the mounting tabs shown are 1 1/2'' long. You will also find Kevlar joining tape at each end of the tube opening.
BVM recommends using the bypass tube cover in our installations.
For contrast, the accompanying photos show a P-200 sized BVM tube for the Ultra Bandit, and a P-70 sized tube for a BVM T-33.
Note how the engine is mounted in the large tube. There is 1/4'' plywood under the fiberglass ears, and we use 4-40 hardware.
Do you know of any reason you could not use this type of mount strap and tees on your engine? What is you engine case diameter?
BVM has mount straps available in various sizes to fit various engines.
1. Mount By-pass to rails since the bypass is wide enough, then mount turbine to bypass by drilling holes into bypass and using bolts or screws to hold in place -this is sort of way BVM does it I think, but I am unsure if this is a BVM bypass and if it presents safety and structural integrity issues should bypass melt/break, etc... during flight. From the looks of your bypass, it is not a BVM bypass tube.
In the photos your mounting flanges appear to be parallel to the engine mount plates in the airframe, and appear to be three or four inches long.
BVM bypass tubes feature angled mounting tabs designed to use the BVM cast aluminum tees that come with our engine mount strap kits. For this reason, the mounting tabs shown are 1 1/2'' long. You will also find Kevlar joining tape at each end of the tube opening.
BVM recommends using the bypass tube cover in our installations.
For contrast, the accompanying photos show a P-200 sized BVM tube for the Ultra Bandit, and a P-70 sized tube for a BVM T-33.
Note how the engine is mounted in the large tube. There is 1/4'' plywood under the fiberglass ears, and we use 4-40 hardware.
Do you know of any reason you could not use this type of mount strap and tees on your engine? What is you engine case diameter?
BVM has mount straps available in various sizes to fit various engines.
Shaz
08-12-2010, 03:15 PM
#7
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RE: Would a By-pass like this hold the turbine well?
Another approach would be to use some alum channel (same width as your turbine strap). Attach the channel using the existing two fasteners on the strap and then bolt to the existing rails using a blind nut.
Rick
Rick
08-12-2010, 11:27 PM
#8
RE: Would a By-pass like this hold the turbine well?
Shaz, that's an easy fix...butt glue (hysol) ply rails to the edge of the existing rails, then strengthen the joint by hysoling a 1/4" ply plate overlaping the glue joint u just made by an inch or so....do this on the bottom of the rail and ther are no issues or changes to the thrustline....OR....just rip the rails out and replace them with wider rails and you're done...prob whatI would do....no worries....
Burning kero in MN now......
Ryan
Burning kero in MN now......
Ryan
08-13-2010, 09:22 AM
#11
RE: Would a By-pass like this hold the turbine well?
ORIGINAL: sskianpour
Thanks Ryan, that makes sense. Enjoy MN, I hear its hot and humid, but the air is thick and the jets come in niiiice and slow. Give Clark a hard time for me!
Shaz
Thanks Ryan, that makes sense. Enjoy MN, I hear its hot and humid, but the air is thick and the jets come in niiiice and slow. Give Clark a hard time for me!
Shaz
08-13-2010, 02:01 PM
#12
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RE: Would a By-pass like this hold the turbine well?
ORIGINAL: sskianpour
Thanks Ryan, that makes sense. Enjoy MN, I hear its hot and humid, but the air is thick and the jets come in niiiice and slow. Give Clark a hard time for me!
Shaz
Thanks Ryan, that makes sense. Enjoy MN, I hear its hot and humid, but the air is thick and the jets come in niiiice and slow. Give Clark a hard time for me!
Shaz
On hot humid days, the "Density Altitude" is higher" than on cool dryer days.
Google Density altitude.
08-13-2010, 04:27 PM
#14
RE: Would a By-pass like this hold the turbine well?
ORIGINAL: Harley Condra
Actually, hotter humid air is thinner...not denser. It may feel denser because of heat and humidity, but the air is actually thinner in hot, humid environments.
On hot humid days, the ''Density Altitude'' is higher'' than on cool dryer days.
Google Density altitude.
ORIGINAL: sskianpour
Thanks Ryan, that makes sense. Enjoy MN, I hear its hot and humid, but the air is thick and the jets come in niiiice and slow. Give Clark a hard time for me!
Shaz
Thanks Ryan, that makes sense. Enjoy MN, I hear its hot and humid, but the air is thick and the jets come in niiiice and slow. Give Clark a hard time for me!
Shaz
On hot humid days, the ''Density Altitude'' is higher'' than on cool dryer days.
Google Density altitude.
our density altitude based on weather.com's stats today is 9651 feet...I guess you are right though, I was saying hot and humid MN is better for planes, and I was wrong, it is never better when hot and humid vs. dry and cold. In fact MN is only better than Denver since its is thousands of feet lower, not because it is hot and humid.
regardless, thanks for the help all on the turbine mounting issue...
Shaz
08-14-2010, 09:10 AM
#15
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RE: Would a By-pass like this hold the turbine well?
Shaz, Why couldn't you bolt the ply extensions you would make to your existing mounts but mount your turbine strap mounts to the underside rather then on top?? That way you don't gain that extra amount that you are trying to avoid. Than if you ever need to take the turbine out, just un-bolt the fabricated mount you made from the stock mounts and out you are.
