FE Whiplash

[Roxyflash]

Im building this hull for Ray and need some ideas on the motor compartment.What im thinking is the former up from the transom i closed it off from there to the transom. On the former from the nose where epoxy ends i will make a large radiobox motor compartment lid that will go to the former next to the transom.If any one has pictures of there setup i would like to see them.Heres some pictures.

http://i176.photobucket.com/albums/w165/Ro...sh/IMG_1730.jpg

http://i176.photobucket.com/albums/w165/Ro...sh/IMG_1728.jpg

http://i176.photobucket.com/albums/w165/Ro...sh/IMG_1727.jpg

 

[Raydee]

Bruce I have a couple idea's that may work perfect. I know some of the other guys that built the hull cut the front end of the cowl off and glued it to the hull but I like this way better so far. The way you have it now I will most likely stick the lipo's way up in the front of the boat and the motor behind them. All you really need to do now is make a lip all the way around the hull and I can make a nice Plexi sub hatch that will be taped down making the hull water tight. It won't be a really easy 4 point tape down but it will be close enough. As long as its water tight it will work fine. Then I can just use a couple orings to hold the top hatch down just so it doesn't blow off in a 60 mph crash

 

[Raydee]

Ok guys don't laugh at my horrible drawing skills but here is what I mean.

 

[Roxyflash]

Got the nose trimmed.Will do as Ray suggested and make a tape on lid for it.I will use some 1/8 square dowel on the hull then make a lid out of 1/16 plwood.Heres another picture.

http://i176.photobucket.com/albums/w165/Ro...sh/IMG_1731.jpg

 

[jayt]

I can't see how you will get the CG anywhere near where it needs to be using the component positioning shown in Ray's drawing, particularly with LiPos. The CG will need to be close to the rear of the sponsons, and that won't happen unless the motor and/or cells are moved farther forward. I'm not too wild about removing a critical structural bulkhead either....

On his SAW record-setting Whiplash, Brian had to add about 12 ounces of weight to the bow to get the CG right. You may have to do the same, so maintain access to the forward-most compartment.

.

 

[Raydee]

I will not be running SAW or anywhere close to 90 mph so if the cg is a little back I don't think it will be that big of a problem. If I have to I can add a litlte weight to the front of the hull. Also I can put the heavier motor up front and the cells behind it if that helps move some of the weight more forward. I laid this out both ways before I sent the hull to Bruce and the CG wasn't bad.....not perfect but not bad either.

The bulkhead comment has me concerned though, if I put the motor up there then like Jay said maybe we should leave it Bruce. Jay has been at this game much longer than I have and he knows his stuff.

 

[Raydee]

This is basically the setup I was after besides except the hatch setup. I do think the heavier motor may be better up front and the lipo's behind though and that will most likey be the way I set the boat up once its all done. From what I am told this boat runs real good in the mid 50's with no issues.

http://img.villagephotos.com/p/2007-8/1274297/whip4.JPG

http://img.villagephotos.com/p/2007-8/1274297/whip5.JPG

http://img.villagephotos.com/p/2007-8/1274297/whip6.JPG

 

[Dr. Jet]

I am experiencing a similar balancing act with my MHZ Miss Madison. I finally wound up burying the motor (the heaviest component) as far forward under the canopy as possible, and the batteries as far forward as possible (see photo of preliminary component layout). This leaves some room to adjust the batteries aft; but in order to move the balance point forward, it will take some weight in front of the motor. Perhaps a big Rx battery pack would work for the necessary weight.

 

[Ub Hauled]

Doc Jet,

I have recently bought that hull as well.. well, kinda recently.. it was a month ago.

MHZ has yet to deliver it... did you get the model with the hardware included?

It looks like a fun little boat. Any suggestions?

I am experiencing a similar balancing act with my MHZ Miss Madison. I finally wound up burying the motor (the heaviest component) as far forward under the canopy as possible, and the batteries as far forward as possible (see photo of preliminary component layout). This leaves some room to adjust the batteries aft; but in order to move the balance point forward, it will take some weight in front of the motor. Perhaps a big Rx battery pack would work for the necessary weight.

 

[BACKEMF]

Those last 3 shots are of my buddy Larry's boat and here is another.

He uses a shelf with the permanently mounted front cowl portion. This is a very good setup, and I believe he has the front bulkhead removed as I will do also shortly (build just started). You will need to signifcantly re-inforce the nose section with wood and glass as Larry has and something else I will do is build in a Carbon ron 3/8" through the front wood nose block and into the sponsons as a brace.

I do not plan to put the "width" taper in the nose only the "height".

I've got some leftover Carbon Kevlar 4 oz cloth kicking about...

 

[Raydee]

Well I got a call from Larry the other night and he gave me some great info and some tips to get the CG more forward. I am going to try to mount the motor as far forward as possible with the cells behind and see where that gets me. If the cg is still to far back I will do some modding and move the cells to the front and the motor behind. I should have pics of the finished hull soon.

 

[TRUCKPULL]

Ray

I forgot to tell you that you may have to but a bubble in the sub hatch to clear the motor.

Larry

 

[Jason]

Hi Guys

What side are you running your rudder on on the Whip.

On the left or right side of boat ( when looking from the stern )

just wanting to get an idea what is the best setup

hopefully a few of you that have these running can let us know

 

[TRUCKPULL]

Feft.

Larry

 

[BACKEMF]

Feft = Left

 

[BACKEMF]

Ray
I forgot to tell you that you may have to but a bubble in the sub hatch to clear the motor.

Larry

OK, I'll keep that in mind.

Larry, what size cable are you running? .150"?

 

[TRUCKPULL]

Ray
I forgot to tell you that you may have to but a bubble in the sub hatch to clear the motor.

Larry

Ray S.

The quote was for Raydee,- about his boat.

Yes .150 cable.

Larry

 

[BACKEMF]

GRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR!

:angry:

 

[Dr. Jet]

Doc Jet,I have recently bought that hull as well.. well, kinda recently.. it was a month ago.

MHZ has yet to deliver it... did you get the model with the hardware included?

It looks like a fun little boat. Any suggestions?

UB,

Sorry to take so long to get back....and to hijack this thread

I have a bunch of projects on the boards, so I have yet to finish this one and put it in the water. I have had some contact with MHZ, and they recommend a "typical" balance point around the middle to the aft edge of the turn fin; so with LiPos, a bit of "creativity" in installing components is required. My past experience with MHZ hulls has been very positive, and I expect no less with this hull. It is an interesting design with asymetric sponsons and a "scale" cockpit offset (to the left). MHZ mounted the drive in the center of the transom, so the drive appears offset in the attached photo.

I chose a motor with a Kv of 3400 rpm/V to run on 2S2P LiPos with props in the 31~33mm or even 35mm range (the NeuMotor has a lot of torque and can turn a fairly big prop). FE Calc predicts that I can use this same motor on 3S if I cut-down a 29mm prop to 27~28mm. If you plan to run 3S exclusively, I would look at a motor with a Kv around 2500~3000 rpm/V.

Yes, I got the hull with the hardware installed, and I am pleased with the quality and suitability of the equipment. It does force you to use the 4mm threaded Graupner props, but they are available in a number of sizes and pitches, and are generally good quality. An added bonus is the fact that they are cheap and generally require no effort in balancing.

As you may know from "The Red Board", I have opted to explore the small and cheap end of the FE spectrum this season, and say "To Heck" with all this ever-more-expensive FE racing. Besides, our pond is just becoming too small to race modern FE hulls, even N-2! This hull will be my "high-end" micro with Neu power and 2P LiPos. I have several plans for some really cheap racers this season: I have just joined the hull of my BBY micro-twin cat this morning. It sports two brand-new brushless motors and two ESCs with a total price for both of them of less than $60 delivered to my door. That is hard to beat! I have a BBY micro hydro that I plan to have ready-to-race for under $100 (plus some stuff lying around the shop). I have even gone so far as to work on shrinking Jay Turner's "Electric Pool Racer" to 15" and make a REALLY CHEAP racer.

 

[Raydee]

I can't see how you will get the CG anywhere near where it needs to be using the component positioning shown in Ray's drawing, particularly with LiPos. The CG will need to be close to the rear of the sponsons, and that won't happen unless the motor and/or cells are moved farther forward. I'm not too wild about removing a critical structural bulkhead either....
On his SAW record-setting Whiplash, Brian had to add about 12 ounces of weight to the bow to get the CG right. You may have to do the same, so maintain access to the forward-most compartment.

.

Jay you were right like always. I laid everything out and the closest I could come on the cg is 2" from the back of the sponsons. I spent the last couple hours removing the front bulkhead just enough to fit the lipo's up front and still maintain some of the structure. Larry gave me a couple idea's to enclose the front end so I can still keep the hull water tight and it should work good. The Lipo's are going to be a tight fit so I may still have to move the motor a little farther back than i really want to but I should still be able to get the cg at 1/2" to 3/4" from the back of the sponsons. I may end up adding a little bit of weight up front just to be safe. I am going to mount the strut and rudder tonight and enclose the front end tomorrow, mount the motor and run the stuffing tube.