GRV-2 Jet Bike Project 10/22/09

Posted on October 22, 2009

       The big day is finally here!!! After many months of hard work and pure determination I will finally see if the GR-7 can haul it’s weight (and mine for that matter). A lot of preparation has preceded this day and I could not be any more excited to get the Turbochopper rolling. However I must not forget that the most important goal I had set out to accomplish has already been fulfilled in the education I received building this project and the ones before it.
       I would of never guessed that building the
GR-1 would of lead up to this point but it has and I am ready for the next step. Riding the GRV-2 will be like a final exam for this course encompassing many fabrication and engineering challenges. Ultimately it will be the reward for picking the GR-7 project back up and seeing it through to completion. (something that took a couple of years to finally do ;0)
       Unlike my
GRV-1 Turbotug I needed a lot of room to test the jet bike. El Mirage dry lake in California was the final choice for a testing location due to its super flat surface and wide open spaces. The flat riding surface will provide the most accurate speed reading and the 6 mile long lake bed will surely be enough room for the bike to roll out before reaching terminal velocity.
       The GRV-2 and my test equipment was hauled up to the dry lake on a beautiful Saturday morning. I was accompanied by my brother Mike Giandomenico and good friends Kent Gallacher and Andreas Blaser.

       We arrived at El Mirage at about 8:30 am and set up shop on the east end of the lake bed where the riding surface is super smooth. The air was still and hardly a soul was to be seen on the lake bed. 

       We had brought with us several video and still cameras to document the trial runs including a wireless on-board camera for a unique view of the Turbochopper. Test equipment included a GPS unit and a radar gun to track my speed across the course. I also brought out my 250 cc shifter cart (seen below) to scout the course out that I would soon be be riding.

       While I was busy warming up the GR-7 the crew was busy setting up the course. A GPS unit was used to set up marker cones in a straight line about a 1/2 mile in length. We were not sure if the 1/2 mile course would be long enough but we were sure to find out :0)

       I prepared my nerves for the first run checking over the operation of the engine. All seemed A-OK as I cycled the GR-7 all the time wondering what would happen in the next few minutes.

       The air temperature at the lake bed was about 82° F and climbing which was less than optimal for a turbojet. However the engine’s EGT (Exhaust Gas Temperature) was typically constant only showing a slight rise in oil temperature due to the warmer ambient air through the oil cooler.

       I prepared my safety equipment including my new riding jacket and helmet. I had forgotten my riding boots (shame on me) so my sneakers would have to do. A CO2 fire extinguisher was at the ready along with my Safari van chase vehicle should the crew need to get to me in an emergency.

       I drove the course a few times with my go cart at about 50 MPH to get a feel for the course that the guys had set up for me. I was looking for FOD or any other debris that could get in my way during the run. After I was satisfied with the course I suited up for the first trial.

       I fired up the bike and rolled out toward the starting line about a 1/2 mile away from camp. The bike lumbered along at 3/4 throttle not showing much acceleration at first but improved with speed. I wasn’t sure how the bike would handle at speed so I used this opportunity to get a feel for the steering as I slowly made slalom turns on the approach.

       The moment of truth!!! Are you nervous yet (I am at this point :0)!!! I rode the bike in a wide turn around the last cone and rolled the throttle up to about 80%. The bike picked up speed and I began to feel the wind push on me as I moved down the course. The bike was handling great as I adjusted my course a bit closer to the cones.

       Feeling a bit more confident that the bike was going to hold together I pushed the GR-7 to 100% and tucked into the frame. The wind was really rushing by me now!!!

       I was really amazed at how smooth the bike was riding considering most of what I have ridden before had a vibrating piston engine. I could not feel anything but the acceleration and the wind pushing on my helmet. The sweet whine of the GR-7 was a real plus in the experience ;0)

       I approached the speed trapp with caution hoping I would not loose control and hit my crew. I passed the radar gun and applied the brakes gently as to not break traction.

       I turned the bike around and rolled on back to the crew to see what the bike did. My brother Mike was happy to report that I had reached 45 MPH which was well beyond what I had hoped for. Needless to say we were ecstatic and the need for speed was born.

       I headed back to camp to cool of the engine and recharge the battery. I was sure at this point that I could go faster given the fact I was still accelerating at the end of the 1/2 mile run. We were determined to break 50 MPH so the bike was fueled back up and out to the course I went.

       I rolled the bike out to the starting line and gunned the engine. I would give it my all this time and pinned the throttle. The bike picked up speed as I set my sights on the finish line. I tried to duck down as much as I could considering the bike has no faring. The warm desert air was filtering through my helmet as the GR-7 was hard at work pushing the combined weight of 530 pounds across the lake bed.
       The sensation of speed was lessened somewhat by the silky smooth ride and featureless terrain. The wind was the only real indicator that I was moving right along.

       By now the GR-7’s oil temp was approaching 240° due to the ambient air temperature of 98° F. The Turbochopper was singing right along as it rocketed past the radar gun. As soon as I applied the brakes I could tell I was going faster than before. There was a lot of stored energy in my momentum and the brakes were finally getting a good workout.

       I turned the bike around and rolled back to the trapp. I could see it in the faces of my crew that we had done it! My brother Mike handed me the radar gun and to my surprise it read 52 MPH!!!

       According to the GPS unit that I had carried in my back pocket we had hit 52.1 MPH at the very end of the run. This was far beyond my expectations for a non-afterburning DIY turbojet project. Considering that the brakes were a bit draggy and the bike has no faring I would call this a success!!! :o))))

     See the GRV-2 Jet Bike Trial Runs video here!!!

       As the day progressed it became apparent that it was too hot to further test the GRV-2. However I am sure the bike will go faster with a longer course and some minor modification to the brakes and bearings. I indeed need more speed!!!!

       We packed up camp shortly after noon and headed back home for a victory meal at the local Mexican restaurant. What an incredible day!!! It is not too often you get to ride a jet powered motorcycle across a famous lake bed!!!

       I would definitely like to thank my fearless crew for helping me test the bike. I think we will all remember this day and the excitement of the moment :0) Thanks guys!!!!!

       So now you ask what now??? I’m not sure but I definitely want to go faster. I think I can do some more work to the bike and come back out to beat the 52 MPH mark. Maybe even add an afterburner to the engine to squeeze out a few more pounds of thrust.

       I really enjoyed this project and I could not have pictured a better “finish” to the story. I thank everyone who supported me in my quest including my beautiful wife Stacy who has NEVER complained once about me working on the project. I am one lucky guy :0)))

       I would also like to thank all of the readers for motivating me to finish the GR-7 and get the project back into gear. Without all of you guys the engine would still be on an engine stand gathering dust. Thanks for all of the encouraging e-mails everyone!!!!

       Thanks for joining me in this adventure. Until then keep experimenting my friends!!!!

Don R. Giandomenico -


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