Gas engine class(es)

[MarkScott]

The Aeromarine Predator X 50 is actually 49" long.. I'm going to start building up some WOF using JD's 47" Solution plans. Before you add the comment Walt, these will be the 47", not the 45.+ that was done the first time around Hate that shrinking wood I used before :blink: :lol: :lol:

 

[waltr]

The Aeromarine Predator X 50 is actually 49" long.. I'm going to start building up some WOF using JD's 47" Solution plans. Before you add the comment Walt, these will be the 47", not the 45.+ that was done the first time around Hate that shrinking wood I used before :blink: :lol: :lol:

:lol: :lol: :lol: :lol:

I never put it in the water so I really never found out if it was going to grow back to 47" like you said it would

 

[rcpilotbill]

these are some great ideas...

I agree with you all

Bill

 

[1ernie lafleur]

I do plan to build a gas tunnel using the MHZ lower which has other than a 1 to1 ratio . I am thinking the smaller prop on the higher ratio will be good for handeling . I hope the rules dont limit things to the 1 to1 only. ERNIE

 

[Gator 340]

Hey Ernie how you been long time no hear from. So tell us about this MHZ lower you are going to run this is the first I have heard of this unit I think :blink: . Do you have any pictures you can share with us. What hull are you planning on running did you talk Mr Mark into building a gas hull if so sweeeeet. By no means do we want to discurage any body from building a gas boat but we do need to get the guide lines drawn up and submited to the organizations IMPBA and NAMBA because right now we are just a bunch of red necks with big tunnel boats I am going to beat James to the Question ARE YOU COMING TO NEXT YEARS TUNNEL RACE.

 

[waltr]

Well,

With some of the recent developments with lower questions,I guess we really need to define the rules fairly soon.

I'm in the process of building 4 gas OB boats with the Woodstuff already complete.If gear ratios are allowed,I'm going to have to change direction on my build plans.So,at this point,The other 3 boats have to be on hold until I know what I can build. I know it's a new class,and we want as many as possable to run,but if we want them to keep running,throwing away parts to upgrade later won't keep em interested.

Since these boats aren't cheap,I really don't want to do them twice.

Now,how do we proceed with a positive rule set?

 

[dwb2620]

First off, I don't run gas boats. But, I used to run tunnel boats back in the day. I have been reading this thread with interest in the rule making. I believe that you should be able to run any lower unit whether it is geared ( any ratio ) or direct drive.

Just my .02 worth!

David

 

[waltr]

What ever the rule is,it is.

I really don't care either way,but I have 2 more hulls in house with another coming and before I rigg 3 more,I'd be nice to know.

 

[Gator 340]

This is the part of the hobby we all hate but it has to be done so just like in politics the magority rules. So with that said we need to know what every body has for set up.

Mitch my brother for those who did not know is running an Aero marine hull with a Zenoah 260 and a Aussi lower.

I am running the Ossi F-1 hull with a Zenoah 260 and the Aussi lower.

Steve hearl is running the Aero hull with the Lawless G Drive not sure what motor he has.

Crawford and Bill are running wood stuff hulls with the G Drive lowers. I think they are running Zenoahs for power plants.

Thats the only ones I know for now so PLEASE every body that has a Gas tunnel chime in and tell us what you are running so we can build the rules around every body's set ups. I will say this and I do not mean any disrespect by it but it is just plain fact. There are more Aussi lowers and G Drive lowers out there now than any other foot for these boats. I know that Mulvany has a home made design foot and the dutch have uniq design foot for the gas out boards. So please every body chime in and lets see what we can come up with.

 

[AFIRacing]

I'mn running a Mod 260 Zenoah, Tony are you and your sister and her son coming to orlando, hope so I arriving back in fla on the 12th at midnite planning on heading to orlando on thursday. See ya there buddy!!

Steve Hearl

 

[waltr]

I'm running a Woodstuff right now with a stock Sikk 25 powerhead and a G drive.

Also have an Aeromarine with an Aussi lower being worked on now too.

I don't want to speak for Mark Scott,but he's running an Aeromarine with a WOF on the drawing boad.He runs a Zenoah/G-Drive combo. too

 

[Gator 340]

I'mn running a Mod 260 Zenoah, Tony are you and your sister and her son coming to orlando, hope so I arriving back in fla on the 12th at midnite planning on heading to orlando on thursday. See ya there buddy!!Steve Hearl

What's up gambler hows your trip going. I am not sure we are going to make it down to O Town we have had some issues with mom she went to the ER 2 weeks ago and we finally got her out Monday just to have to turn around and put her back in yesterday she has got some Nemoniea?? we can't seem to get rid of and some other issues. So we will probably stay around and help dad out with her.

 

[rcpilotbill]

That is correct, Mike and I are running the Zenoah and G drive lower.

I haven't heard anything about this other drive, where is it from and can anyone else get one? I suppose my only concern and maybe its unjust, but since the RPM range on the gas engines is limited to say 20k RPM, but the torque and the HP is capable of spinning a geared drive, now you have a lower unit putting 30k RPM (just grabbed a number for instance) in to the water..... obviously this is potentially a huge speed advantage over a person running a direct drive unit with only 20k RPM available.

I would say that we have to consider the drive if it is something that everyone can get, but we are already looking at something here that I brought up at the beginning and simply shows again the urgency in getting guidelines put in place. We have all of the above boats in the water already a couple more that WoodStuff has orders for, 6 more that James has coming in that may or may not be using a drive that could be proven to be obsolete already if the geared drive proves to be an advantage. Echoing what Walt said, due to the cost of these things, I don't think anyone wants to do these things twice.

James and all that are waiting for your OSSI hulls to arrive, what are / where your drive intentions? I can say that the WoodStuff hulls have been ordered with G drives.

By the way I think this is an awesome thread.... a group of interested racers that are actually having a respectable conversation regarding a class rules package..... this is great and I am glad to be a part of it.

Bill

 

[waltr]

Bill,

To my knowledge,MHZ (awesome stuff) doesen't actually have an OB lower.You would have to do some serious machining to adapt they're gear case for an OB leg. No problem for myself and a few others,but they would not be available for the majority. I would also believe there would be an advantage running different gear ratios.And if they now have an OB lower,I'd love to see it.

http://206.206.85.209/xtdoc/catalogue.aspx...mp;store=mhzusa

 

[AFIRacing]

That works,Hope she gets better soon,sure will miss ya. Give brother mitch a grope for me,Tell Juinor to enjoy his summer break from school,Guess we're gonna hafto try to handle Mark UNFEELABE Poole with the south chapter of the TBM.

Sincerly Hearly

 

[Eddy de Vries]

I hope someone is listing all the happy gas outboard tunnel owners ?

These are two Dutch homemade ones with MHZ gearcase.

The left one is Arian's the Ligier boat on http://www.ossis-rc-modellbaushop.de

The right is Marc's (http://www.intlwaters.com/index.php?showuser=1964) an is a modifed lower of Rob Pols an me.

Both use the Peter Oswald boat.

My own boat is modified glassfiber DPI 48 with a flexshaft lower.

Powerheads I can choose of are M&D full mod 231 and 260 (and a Quickdraw 25 HT soon).

http://www.intlwaters.com/index.php?act=at...ost&id=6454

 

[jaxracer]

I'd have to say if you have a geared lower unit then you should be allowed to run it. As far as them being far superior to a direct drive lower, that is an unknown because a true comparision hasn't been made. Though if that was the case then why aren't more people using or developing a geared lower for our .21, and .45 size tunnels. I know a couple guys on this board such as Jerry Wyss And Tim Duggan use a thundertiger geared lower for their .21 sized hulls and while not witnessing their boats run, have not seen any posts or heard any complains about them being 5-10mph faster than everybody. Also according to the rule book, their setups are legal in the nitro class and so I believe this rule should be carried over to the big gas hulls. Maybe they can chime in here and offer a little info towards the geared lowers vs. direct drive lowers as they have experience with both of them.

From my knowledge base and after conversing with a few others, what I can tell is it's a balance thing where yeah, with a geared lower you may be turning 30,000 rpm at the foot but in effect they have to run a smaller prop due to loss of torque in order to maintain that rpm. Whereas with a direct drive lower your turning the 20,000 rpms but have more torque and are able to turn a larger prop. In effect you achieve similar, if not the same results with the direct drive lower as you would with the geared lower. Also keep in mind for each gear you turn, friction is increased which, as everyone knows is a power robber.

It really comes down to personal preference and finding what works for you. By leaving the rule as any lower it leaves guys room for creativity and innovation and won't discourage guys, such as highly experienced tunnel veterans like Ernie, who already have or want to use a geared lower unit, from the class.

Just my .02.

~Mitch

 

[topfuel443]

I will be running an Ossi hull, and a Zenoah on a Lawless lower.

I agree with Mitch Jr, I say run any lower out there, homemade or manufactured. If geared drives were so much better the gas guys would already be using them to set records with... and to my knowledge, thats not happening.

If we start limiting too many things, it will kill the class before it gets started. I think we need to state what the max engine size should be, boat minimum and maximum length should be, obviously it has to be a steerable outboard, yatta yatta yatta...

~James

 

[bzubee]

Don't forget about how well the AMP lower unit worked you do see alot of them at the races.

I will be running an Ossi hull, and a Zenoah on a Lawless lower.
I agree with Mitch Jr, I say run any lower out there, homemade or manufactured. If geared drives were so much better the gas guys would already be using them to set records with... and to my knowledge, thats not happening.

If we start limiting too many things, it will kill the class before it gets started. I think we need to state what the max engine size should be, boat minimum and maximum length should be, obviously it has to be a steerable outboard, yatta yatta yatta...

~James

 

[rcpilotbill]

You all make a good point, from what I am seeing here we have just about met all of the criteria except engine size..... Which gives all a good set of guidelines in which to build our boats..... and plenty of time to have them ready to rock and roll at the World Tunnel Nats next year!!

We have discussed:

Boat lengths - I believe we said up to 60"

Lower Unit design - Any lower unit, production or home made

All the obvious stuff that makes it a tunnel - Basically from any size tunnel rules package

We agree to allow cones for starters

So what does everyone think regarding engine size? - Is there not already a gas class/engine size package for other gas boats.... could that apply here as well?

Bill