Landracing Forum Home
September 18, 2018, 11:19:04 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
News:
BACK TO LANDRACING.COM HOMEPAGE
 
   Home   Help Search Calendar Login Register  


(Note: Donations are not tax deductible)







Live Audio Streaming and Archives of Past Events
Next Live Event: TBD
Pages: 1 ... 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 [75] 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 ... 118   Go Down
  Print  
Author Topic: APS/Ω Gas turbine bike build  (Read 523284 times)
0 Members and 2 Guests are viewing this topic.
wobblywalrus
Hero Member
*****
Offline Offline

Age: 65
Location: backwoods Oregon
Posts: 4714





Ignore
« Reply #1110 on: October 19, 2015, 08:58:46 PM »

Aerodynamic symmetry is not as important if flow is detached and turbulent around the tail.  It becomes a bigger issue if the streamlining is developed to the degree that flow is attached to the tail.  Flow will attach to one side and be prevented from attaching to the other 'cause of the exhaust plume.  The pressure differential between attached flow on one side and detached on the other plus the sideways thrust of the exhaust might become an issue.  Splitting the flow so it goes out both sides might help. 

It takes a lot of time and thinking to figure out solutions.  It might be similar to the problem I had with the frame flexing due to the added wind loads and weight of the fairing.  Finally, after years mentally and physically wrestling with the problem, the solution was to add some strength to the fairing and its anchor points so it gives the chassis the needed rigidity.  Some fixes are not obvious.  it just takes time to figure them out.
Logged
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1111 on: October 21, 2015, 05:16:23 AM »

At which speeds will side winds and assymetrical fairings start to become a problem with full fairing bikes? 300++km/h or can it happen at such low speeds as 200km/h if the conditions are severe enough?

The bike ran straight as a train at 275km/h but it might very well develop an instability once I get it past 300, no way of knowing before I have tried it I guess.
Logged
gidge348
Jr. Member
**
Offline Offline

Posts: 41




Ignore
« Reply #1112 on: October 21, 2015, 07:18:47 AM »

At which speeds will side winds and assymetrical fairings start to become a problem with full fairing bikes? 300++km/h or can it happen at such low speeds as 200km/h if the conditions are severe enough?

The bike ran straight as a train at 275km/h but it might very well develop an instability once I get it past 300, no way of knowing before I have tried it I guess.

Hi Anders, I don't think there is any easy way to tell what speed you may get a problem without a lot of calculations, but you will know if it happens. One manifestation would be setting up Karman Vortices.
https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street
You probably would have felt these when you travel close behind a semi truck on the freeway.

Cheers
Ian...
 


* truck.JPG (38.98 KB, 1328x382 - viewed 104 times.)
« Last Edit: October 21, 2015, 07:24:23 AM by gidge348 » Logged
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1113 on: October 23, 2015, 10:54:29 PM »

Hi Ian,

Then I´ll stop worrying about the aerodynamics for now and focus on getting the water injection built and tested before next summer, I have made a few changes to the fairings and driving position so I am looking forward to run the bike and find out how fast it will go on the mile.

Cheers!
/Anders
Logged
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1114 on: October 24, 2015, 12:58:54 PM »

I ran the bike this afternoon to test the bearing modification, the rotor spins up much easier now and the engine runs smoother somehow. Earlier it had a grumph to it like it was struggling to keep the revs up but now it just whistles along at 700°C exhaust temp which is 100°C colder than before.

I still haven´t checked the thermocouple for faulty temp readings so it might run even colder than that, I could feel a significant drop in rear wheel torque at idle when I applied the rear brake which isn´t very strange since the exhaust temps were much higher before.



Cheers!
/Anders
Logged
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1115 on: October 26, 2015, 05:20:59 PM »

To help the air enter the engine I added a pair of radiuses to the air box entry tonight.



Hopefully they will reduce some of the supposed turbulence when the air passes the sharp corners and into the air box.



I also made a radiant heat shield for the thermocouple, you can see that slots are cut in the pipe so the exhaust can pass over the thermocouple for faster response.



I´ve also figured out a way to lock the rear brake so I won´t have to start the bike with the rear wheel in the air, a small washer can be fitted behind the brake grip to lock it in place. I´ve just made cad drawings of it and will 3D print it tomorrow in nylon.



Cheers!
/Anders
Logged
bbarn
Sr. Member
****
Offline Offline

Age: 48
Location: Harmony, PA
Posts: 618





Ignore
« Reply #1116 on: October 27, 2015, 07:56:45 AM »

Just because I have seen these before Anders:

Not sure the price on this one is the best, was just showing a sample of what you can get off the shelf or if you were so inclined to make one of your own from this idea.

http://shop.terratrike.com/Locking-Brake-Lever-Set-p/tt600178.htm

The elegance of this one is the simplicity of the design. It's one of those "Why didn't I think of that" type of solutions...someone is getting good money for a simple device...
http://kiwavmotors.com/en/hand-tools/magazi-motorcycle-brake-lever-lock-detail
Logged

I almost never wake up cranky, I usually just let her sleep in.
Queeziryder
Full Member
***
Offline Offline

Age: 51
Location: Royston UK
Posts: 139


Former funnybike racer now Salt crew


WWW

Ignore
« Reply #1117 on: October 27, 2015, 01:42:39 PM »

Hi Anders
Whatever you use to lock the rear brake, attach a large streamer/remove before flight tag so you don't forget to remove it
DAMHIK  grin  shocked

Neil
Logged

Old enough to know better, but too interested in speed to care
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1118 on: October 27, 2015, 04:42:24 PM »

bbarn: Thanks for the hint, that is a clever way of locking the brake. My version turned out even smaller in size so think I´ll go for that design.

I printed the rear brake lock wedge today.



It seems to stay in place as well, good thing so I won´t have to buy a snowmobile brake caliper which has an extra lever for locking the brake in place.



As you suggested Neil I have the wedge fitted to the safety cord so I cannot lose it or forget to remove it, that is good since I tend to forget everything once the bike is running. Smiley



Cheers!
/Anders
Logged
Glen
Global Moderator
Hero Member
***
Offline Offline

Age: 83
Location: South West Utah
Posts: 6978

SCTA/BNI timer 1983 to 2004, Retired,. Crew on Tur



« Reply #1119 on: October 27, 2015, 06:02:00 PM »

Anders on the new intake be sure to cut the sharp corners off at the top and bottom of the new addition. cheers
« Last Edit: October 27, 2015, 07:18:35 PM by Glen » Logged

Glen
Crew on Turbinator II

South West, Utah
Old Scrambler
Sr. Member
****
Offline Offline

Age: 71
Location: Plymouth, WI
Posts: 663


Going Fast - Slowly




Ignore
« Reply #1120 on: October 27, 2015, 07:14:53 PM »

Anders.............regarding the air-intake...........speed causes a lot of crazy things to happen to the air behind a fairing. I have no idea how much air you need. At some unknown speed you may have somewhat of a vacuum shocked  What is the possibility of extending the air-intake to the inlet in your fairing?  Take a look at the intake-ducts on an F-15 or newer USAF fighter-plane.  Also..............do you need clean air?  What would happen to your turbo-vanes if some SALT was ingested?   
Logged

2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2016 AMA Record - 750cc M-CG HONDA CB750 sohc - 130.7 mph
2016 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 137.7 mph
Chasis Builder / Tuner: Dave Murre
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1121 on: November 01, 2015, 02:57:17 PM »

Anders on the new intake be sure to cut the sharp corners off at the top and bottom of the new addition. cheers

I just went out and filed them down a bit to avoid the risk of cutting up my arms while working on the bike, it felt wrong somehow since my father used to tell me never to cut corners... smiley

Anders.............regarding the air-intake...........speed causes a lot of crazy things to happen to the air behind a fairing. I have no idea how much air you need. At some unknown speed you may have somewhat of a vacuum shocked  What is the possibility of extending the air-intake to the inlet in your fairing?  Take a look at the intake-ducts on an F-15 or newer USAF fighter-plane.  Also..............do you need clean air?  What would happen to your turbo-vanes if some SALT was ingested?  

The engine needs roughly one cubik meter of air per second, and as you say it is impossible to estimate by the looks of the bike how the air is passing through the fairing and into the engine.

I really need clean air, any salt or sand particles will wear the compressor wings down in no time at all. If it wasn´t for that I could have made a simple ram air scope that takes in air from the sides behind the front wheel, much easier and much better air flow.

I heard a rumor about the Y2K gas turbine bike trying for the land speed record but it didn´t even make it out of the pits before the engine intake screen was clogged with salt.

There is another difficulty involved as well, the intake duct needs to work in both low and high speeds. At stationary/low speed the engine must be able to suck air through it without restrictions, so a long and tapered ram air intake that works perfect at high speeds would choke the engine.
« Last Edit: November 01, 2015, 04:10:56 PM by Mobacken Racing » Logged
Old Scrambler
Sr. Member
****
Offline Offline

Age: 71
Location: Plymouth, WI
Posts: 663


Going Fast - Slowly




Ignore
« Reply #1122 on: November 02, 2015, 01:21:40 PM »

I am trying to design a Ram-Air intake system for my NA bike with carbs..................I don't know if your turbine needs ram-air......or a duct through which it SUCKS air.....but I know it needs CLEAN air and possibly QUIET air.  Your speed alone could move INTO the air at better than a cubic meter per second. Could you build a box (horseshoe around the frame just aft of the steering stem) with a sizable intake duct (split around the the stem) to the relatively clean air above your front fender?  The bottom ends of the box would feed the turbine. You may be able to install some type of high-flow filter in the box. I don't know if that type of intake should be sealed or if some amount of open-air could be available for slow-speeds without filter restriction. This would allow you to close-off more of the DIRTY air from the front wheel.

The top of the box would be directly below the chin of your helmet..............and quite wide to hold more air..............think about the 'dead' space between your forearms........or maybe I'm dreaming and should take a professional class grin   
Logged

2011 AMA Record - 250cc M-PG TRIUMPH Tiger Cub - 82.5 mph
2013 AMA Record - 250cc MPS-PG TRIUMPH Tiger Cub - 88.7 mph
2016 AMA Record - 750cc M-CG HONDA CB750 sohc - 130.7 mph
2016 AMA Record - 750cc MPS-CG HONDA CB750 sohc - 137.7 mph
Chasis Builder / Tuner: Dave Murre
Mobacken Racing
Sr. Member
****
Offline Offline

Age: 36
Location: Östersund - Sweden
Posts: 825


Turbine junkie


WWW

Ignore
« Reply #1123 on: November 04, 2015, 05:44:02 PM »

I am not sure if having the air intake sticking out the sides is a good idea, it will add lots of drag and in case I tip the bike with the engine running it will ingest lots of dirt.

A quick peek at what I am cooking up at the moment, I have started to design a new 300hp gas turbine for the bike which should be ready to install in the frame in a year or two. I might have written something about it earlier but here is the story so far.

I have 3D printed out a split pattern for the compressor backplate that I need to get the build going, on the old engine I spent roughly 100 hours manually milling it from a solid chunk of aluminum so if this work it will save me lots of time.





I printed a 3D scanned version of the compressor wheel for comparation.



Here is the rear part of the pattern fitted with dowels.



Last night I made a pair of suitable sized flasks and tonight I made the sand pattern.



I sifted the sand closest to the pattern to get a smooth surface finish for the casting.



I used copper tubing to form the downpour and the vents, the downpour fits to the thickest part of the pattern that solidifies last.



Baby powder is brushed on the surface so the sand won´t stick together when I ram the sand in the second flask.



Looking really good! A couple of minor cracks on the diffusor wedges but that can easily be fixed on the cast part. Time to pull the second pattern from the sand.



I am very pleased with how easy the 3D printed PLA patterns release the sand, I haven´t even bothered to smooth out the raw printed surface with sand paper.



The plan is to cast the part on Friday, keep your fingers crossed! Smiley

Cheers!
/Anders
Logged
manta22
Hero Member
*****
Offline Offline

Age: 79
Location: Tucson, AZ
Posts: 3197


What, me worry?




Ignore
« Reply #1124 on: November 05, 2015, 10:48:04 AM »

Very impressive work, Anders!

Regards, Neil  Tucson, AZ
Logged

Regards, Neil  Tucson, AZ
Pages: 1 ... 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 [75] 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 ... 118   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!


Google visited last this page July 28, 2018, 04:10:40 AM