|
|
Post by Johansson on Mar 30, 2017 11:54:27 GMT -5
As if we hadn´t enough to do already...   We ran the twinturbo jet kick sled this winter at Speed Weekend, finally the engines ran perfectly after a couple of years with oil pressure issues. Unfortunately the combination of hard ice, no brakes and unsharpened sled runners led to a crash when the kick sled steered hard left after engine shutdown no matter how Olov tried to keep it going straight.  According to the GPS log Olov hit the snow wall at 80km/h, he was very lucky not to get hurt. The kick sled was not so lucky, it tumbled a couple of times and was in a sorry state when he got back to the race pits...  A week after the race we ran the engines without problems so they are ok. So, what would be do next? Despite a wide stance and a suspended engine cradle the kick chassis is simply too unstable at speed, so we need a change of plans!  We have decided to build a top fuel style ice yacht powered by the kick sled gas producers coupled to a C20 4th stage turbine powered T700 1st stage axial compressor serving as a turbofan. Topped off with an afterburner of course, John has calculated the potential thrust with afterburner to over 500lbs!  Since Olov and I are both family men there is little time for building anything together, so we have split the project so that Olov designs and builds the tubular chassis and I will build the turbofan module. John Wallis has kindly supported us with both a C20 4th stage NGV and the T700 fan, and we have figured out the main guidelines for the engine so the project is well on its way!  Cheers! /Anders |
|
BFTO
Veteran Member
Joined: February 2016
Posts: 128 
|
Post by BFTO on Mar 30, 2017 12:58:04 GMT -5
This project will be epic!  |
|
dieselguy86
Veteran Member
Joined: September 2014
Posts: 186
|
Post by dieselguy86 on Mar 30, 2017 14:39:03 GMT -5
VERY interested in how you power the fan. Usually its powered by a seperate spool, will yours be this way? This will be absolutely AWESOME to watch!!
|
|
Deleted
Joined: January 1970
Posts: 0
|
Post by Deleted on Mar 30, 2017 14:55:36 GMT -5
Going to be good :-)
|
|
|
|
Post by Johansson on Mar 30, 2017 16:02:16 GMT -5
Thanks guys, this will be a fun build for sure! Plus it has the potential for some serious speeds. Here is the schematics for the engine, the two gas producers will feed into the C20 NGV and turn the power turbine which is fitted to the same drive shaft as the T700 fan. The rotational directions for the turbine and fan makes the arrangement look a bit weird with the gas producer exhaust pointing forward/upward but that we have to live with.  I started by machining away the welded in labyrint seal in the NGV to get a clean surface for mounting the NGV on the shaft tunnel.  Then I bought a length of thick walled seamless 2142 steel pipe to make the shaft tunnel out of.  The NGV test fitted on the shaft tunnel.  A pair of 3.5" v band clamps are ordered which will be the entry points for the sheet metal twin entry snail housing for the NGV, a pair of flexible exhaust ducts will later fit between the gas producers and the turbofan turbine to allow for some heat expansion.  I will snatch a picture or two from Olovs progress on the chassis, or even better if he finds the time to post it here himself. I´ll ask him. Cheers! /Anders |
|
|
|
Post by racket on Mar 30, 2017 16:33:38 GMT -5
Hi Anders
You guys are really getting into this build :-)
Some serious speeds indeed with such a streamlined machine , those first jet fighter aircraft had <1,000 lbs of thrust .
Nice solid shaft tunnel.
Cheers
John
|
|
|
|
Post by Johansson on Mar 30, 2017 16:42:24 GMT -5
Hi Anders You guys are really getting into this build :-) Some serious speeds indeed with such a streamlined machine , those first jet fighter aircraft had <1,000 lbs of thrust . Nice solid shaft tunnel. Cheers John Hi John, We need to, Speed Weekend 2018 is fast approaching so no time for slacking around. Our friends with the pulsejet sled has driven almost 250km/h sitting on top of the sled with 230kg of thrust, so I think that 300km/h is within reach if we get the engine running properly. Solid as a rock, it will be the anchoring point for the fan thrust so there is no reason to chase weight. By the way guys, Olov and I have finally started a Mobacken Racing facebook page, you can subscribe to it if you want at www.facebook.com/mobackenracing/Cheers! /Anders |
|
gtbph
Veteran Member
Joined: August 2013
Posts: 101
|
Post by gtbph on Apr 1, 2017 4:22:41 GMT -5
Hi Anders, Wow, cool project, and that engine is just incredible! My first thought is how to add wings to this If you really add an afterburner to it I'll have to come to Speed Weekend to see this monster live if I have time. I would anyway like to see this event once, here in Switzerland you can barely open a beer can outdoors without the neighbors complaining. Cheers, Alain |
|
|
|
Post by jetjeff on Apr 1, 2017 13:28:09 GMT -5
Olov / Anders,
Nice work on the top fuel ice yacht. Are you planning on making the runners? If yes, then I can give you some pointers on making very fast runners. I used to race DN iceboats and have made stainless runners out of 410, then heat treated. The bottom is a 90 degree angle, but the runner must have a crown to it. The trick is to bend your runner stock on your mill with the ends shimmed. The head of the mill is indexed to 45 degrees. The top of the crown should be where it pivots on the runner plank. May not make a lot of sense without a picture.
Regards
Jeff
|
|
|
|
Post by jetjeff on Apr 1, 2017 13:39:28 GMT -5
Here is a pic of my DN runners. Class rules said the body of the runners must be wood, you could use aluminum stiffeners. Regards Jeff  |
|
|
|
Post by Johansson on Apr 1, 2017 15:06:21 GMT -5
Olov / Anders, Nice work on the top fuel ice yacht. Are you planning on making the runners? If yes, then I can give you some pointers on making very fast runners. I used to race DN iceboats and have made stainless runners out of 410, then heat treated. The bottom is a 90 degree angle, but the runner must have a crown to it. The trick is to bend your runner stock on your mill with the ends shimmed. The head of the mill is indexed to 45 degrees. The top of the crown should be where it pivots on the runner plank. May not make a lot of sense without a picture. Regards Jeff Hi Jeff, We´d like some design help with the runners for sure, thanks a lot! I´ll tell Olov this and we´ll get back to you once the chassis is built and we start on the steering and runners. Cheers! /Anders |
|
|
|
Post by olovselander on Apr 2, 2017 2:32:01 GMT -5
Hi all! We´re happy for all input we can get, especially on the chassis and runners. Since we´re limited to only one race a year, one problem to notice and solve might be one year of lost time. So every problem we don´t have to find out ourselves might be one year of saved time. To be honest i don´t have any experience in designing a tubular chassis so this will only a be bunch of guesswork and we´ll se how things turn out. The thing we at least think is different from a caris that we won´t have any of the twisting forces from drivetrain and wheels so this will be more like a dead stick. And also in suspension we should have a lot less factors to deal with, no wheel hopping and such. So, i guess we´ll do with simpler components and design for suspension too (At least that´s what i think!!) So feel free to comment!  However, the build has begun and i´ve setup the mill for some tube notching. I´m just using el cheapo "china bi metal" holesaws. We´re saving on the tubing, at least to start with. Felt stupid going with expensive CrMo tubing before we even know we have a working design so we´re going with regular welded steel tubes. And so far i think it will do great.  It works not perfect maybe but good enough.  As you see much is el cheapo, i´ve made a levelable fixture for the frame of a bunch of wood.  This is the bottom part all done, with that set a side i changed some dimensions in the fixture and today i´m going to make the top part.   Had to make the "standard jumping test" to se how stiff the sides will be. And the result was better than expected! |
|
|
|
Post by olovselander on Apr 3, 2017 3:38:59 GMT -5
The frame of the yacht is growing. Made the top part yesterday and cut the tubes for the sides.  It's a little bit of a mess trying to hold, meassure and weld at the same time but i tacked it on some spots now and it seems ok.  |
|
CH3NO2
Senior Member
Joined: March 2017
Posts: 455
|
Post by CH3NO2 on Apr 3, 2017 12:45:40 GMT -5
Anders, Your work is an inspiration. The things you have done are unbelievable, not normal and insane. In a good way. |
|
|
|
Post by Johansson on Apr 3, 2017 13:05:28 GMT -5
Anders, Your work is an inspiration. The things you have done are unbelievable, not normal and insane. In a good way. Thank you very much Hydrazine! I just need to point out that Olov is just as responsible for much of the stuff I have posted here, the turbine bike and JU-02 build are my own but the jet kick sled and this turbofan ice yacht are joined efforts. Cheers! /Anders |
|
