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WallyGator

Well-known member
Okay,
I have paid attention to every post about noise(I Think) and I should do something. I run a JR J 0-540 on a 5 blade warp drive. I need to cut the noise. When I bought this boat it was and is my first new built airboat.All my other have been cut and paste specials.
I get my knowledge from you guys here on the forum so this is what I want to do.

1)Put crossover exhaust.
2)Round the baldes
3)Add another blade and change the pitch on the first one and then lower the pitch on the last 5.
All of these were ideas are from other members and airboters who have done it.
Now the question is what of this can I do myself?.

The exhaust looks buildable for me but I have concerns about back pressure!! I was told and have heard people talk of this has your friend and enemy.????Also what muffler to put on, everone has a choice that they like.OR do I just go to some one and have it built,I thought I might call JR J and see if they would do it?
2)Rounding the blade.Being a pilot and owning a plane myself I know of this but also know that if you balance the blades when you do this it will also help just dont have the balls to cut up my new boat yet.
3)A new blade and picth change.I have run with some people in Citrus county with the same boat configuration who have done this and man is it quiet or should I say it is not has harsh a sound.They set the first blade at 6* and the the blanace of them at 5*.This I do not know because I have not ever seen it done by anyone else.

SO here are my issues and now as happens here I would like some input. I live in Alachua county and should be one of those leading the way to noise reduction and safe airboating by the code.It is a family event for us and it needs to be preserved for all.
WallyGator
( see you in the chat room tonight)
 
WallyGator,

First, I want to say that I have not tried this, it is just an idea. If you are going to go to a 6 blade warp drive, why not go with the turbo hub (two layer)? They are known to be quiet. Here is a picture of cchardt's prop, I hope you dont mind cc):
cage.jpg


Below is the latest in motorcycle crossover exhaust and I like it:

crossover_2.JPG


If you go from the headers under the engine and then forward with the crossover it would give you plenty of room to loop the pipes around (180 degrees) back toward the stern and give more room for mufflers. I don't know why the mufflers that cntry used would not work with your 540.

http://www.flopro.com/FPovalsmall.htm

I would not be surprised to see you pick up a little power with a set up like that, but it would be an experiment. This set up will put hot pipes under your carb, so some sort of drip shield would be a good idea to keep fuel off of the pipes.

I have another idea, but it is so far out there that I almost hesitate to post it. One of the problems with quieting an aircraft engine is that you are stuck with the rpm of the engine with no gearbox. The noise is created at the tips, so my idea is to interfere with the tip vortexes where the reverse flow is. I think this is what the turbo warp drive does.

I want to try to direct the exhaust just outside the prop tip in hopes of interfering with that vortex. I am pretty sure it will change the sound, but I am not sure if it will make it quieter. I woud envision the exhaust tip to be a foot or so in front of and just outside of the prop tip. Please don't laugh

Jim

edit: added pictures and muffler url
 
Good one Jim, I purposely installed a down turn pipe at the end of my exhaust. Then I held it on with a clamp, Every trip I rotated it 90 degrees to see if it makes a difference. Well it did and several people noticed how much quieter my boat became. So that idea works now I haven’t played with the distance from the tip like you mentioned, I just found that aiming exhaust towards the prop in a certain way really lowered the noise the prop made while getting on a plane. I know my boat can run below the DB reg’s I’m not even worried about them anymore!
 
Okay a turbo hub sounds like a great idea. How do I size one for my boat?.I can then sell my old prop or use the blads?. Is that correct or do they use diffrent blades for that.
I will build the exhaust, lay some ideas on me, my dad and I are into inovation and we will build it.
I will get some pictures of the back of my boat together.
Wally
 
Wallygator,

Call Classic at 1-800-228-7977 to talk about the turbo, they designed it. I think you can keep your blades and just add one more. I have heard that they also have the pattern for rounding the blades. I would first try just rounding the blades on the front layer (closest to the engine) I believe the front prop quiets the rear prop. But, ask the guys at Classic they have tried this stuff.

Jim
 
I looked but did not see them, I go to his photo gallery here and just click?When I click on it I only get the one photo what am I doing wrong?.
 
OKay Called CLassic,
NO props in stock but on the way. They have done no cross over but they can.I have a 13 rivermaster with the thru hull cuts for exhaust so moving my pipes up into the cage area would leave me with two holes.

SO the new plan.

Turbo hub six blade.
cross exhaust. I will build, I will build it here.
What are the problems I should look for on an aircraft.I see in the picture he used flex joints and and a cross over from an aircraft.Also what muffler?.
 
Hey W.G. ---I have almost the same set up as you. (0540 & 14 ft glass) I run super-trapp exhaust and a 3 blade Sen. Are you going to the Salt Springs ride at the end of the month? I'll be there if you want to hear it. I'll bring my dec. meter and you can check out different rigs. I've had many comments on how quiet mine is---I think it's mostly because it planes so fast and cruises at 15-1700---just doesn't make a lot of noise at those low rpm's.

Good Luck
Harvey
 
WG< I am interested in your EX., did you make it yourself and add the disk, What parts did you have to order, I have heard you need 15disk per side on the 540?
 
previous post:

The mufflers are FLO-PRO # 3020, I dont know if you can get them except from a muffler shop but surely you can. I dont know if mufflers alone will do it mine is a whole system. There should be some pics up soon if they are not already up. The mufflers retailed for 42.50 each the true-x crossover was 75 retail. The two flex joints were 33 each retail and they are double woven stainless, no corrugated pipe in them at all the ones with the pipe in them dont last as long I am told.

The crossover is automotive not aircraft as far as I know anyways. I added a rather chincy looking side sheild on my cage trying it out before getting a stainless one welded on there and I am not sure if it helped or not. My db meter was not working properly at the ksrvsa picnic so i am not sure of the results of all of it yet.

tuning your header length does work but I am not sure how to calculate it. It also jelps with the power and torque. I added a set of 3" bullets like the old glass packs and it is quieter at idle and I still have not lost any power. with 19 degrees of pitch in my prop I still turn 5000 which is turning the prop about 2400 I will pitch it down once I get a chance to see how slowing it down affects my ground running. I like to run the ground because I cant seem to keep it in the water.

The point is they can be quieted down and must be or we will be banned. I don't care if you run mufflers or not the STATE OF FLORIDA cares and is gonna show us how much they care real soon. So if you don't run mufflers well you better get something on there that looks like one and you better be a lot quieter than most boats are now.

Now if anyone can find anything written down that says flex pipe is an effective muffling device then run flex pipe as long as it is quiet and it meets the definition of an effective muffling device who cares.

I really think straight open headers or stacks are going to be impossible to get away with but maybe you are a better salesman than I am. I don't want to have that conversation with the FWC.

I am not as happy with mine as others seem to be ... I would like to be able to drive up and bump you and you not hear me coming but that is just me. I love the sound of race cars and open headers but not on the lakes and rivers. Anyone can build a loud boat lets see who can build a quiet boat The FWC is gonna be the final judge on who wins and 90db is the finish line at this time. Maybe we can get the law changed to allow a 100db but right now it is 90. So either we comply or we hire a lobbyist to help get it changed so we dont get fined. and while were at it we gotta get it changed to not allow locals to write their own law over the state limits. We also need to get the curfews that have been imposed to get around the noise law restrictions over turned so we can run at night and frog. It is going to be a costly battle and an uphill battle because we have let them get a head start on us and once a law is passed it is harder to repeal it than it would have been to defeat it at the beginning.

Now what is the chances of all of us banding together and moving in one direction?? probably not good so more than likely nothing will change except where we can run our boats and that is a shame. I say that because people have been complaining of the noise for years and our best response has been to give them a one finger salute and tell them to move if they don't like it well folks they have moved and we aint liking it one bit.
 
For those of you that are not familiar with the super trapp this is what it looks like. Paul Dixon uses these mufflers on his 540's I think.

drawing%20copy.gif


They are rather expensive.

Jim
 
Thanks for the info.
I spoke to Jim today and we have some ideas. I will use the part numbers you have supplied.I do have a question. Mydada re I are looking for info on tuning the pipes for length. This should be a clac based on volume of the pistion/cylinder but I am not sure Does anyone know this formula.

In regards to banding together. I think that information is key and the forming of forums and groups has been a big help.I was not able to attend the metting at GTO for the new club in our area but I understand that it went well. I would like to see someone on this forum speak of it if they were there. I posted the pres info they provided here after the metting.

If the more we speak and brain storm this will benifit all of us the better.Or we will be using or boats has planters and I would not like that
 
moodfood":23uut4kh said:
So, my question is, would it be possible to use a V-10 motor on an airboat? ..........Another question is if it is possible to determine the firing order for any other motor, and create an exhaust with pipes of differing lengths to simulate the situation that the v-10 gets naturally so that wave/inverted wave cancel each other out?
Click to expand...

I think a V10 on an airboat, while cool, would be a waste. Very $$$ and heavy, and you can get more cubic inches from a Chevy or Cadillac V8.

However, you are on to something with pulse technology.

Here's something to think about. When you run dual exhaust on an engine, you split the pulses in half. Run a single exhaust or a true crossover system and you double the frequency over a true dual system, and that cancels sound. That's why OEM's have used single exhaust systems over the years.
 
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