Fuel for old KBV72 ducted fan engine?
05-23-2017, 10:29 PM
#2
Hey Jeremy. I think your question may be ambitious for this forum, but there may be an old timer or two still listening.
I used to run up to 20% in my Nelson/BVM engine. From what I can remember, you can go up to 20% nitro before you needed to add head shims to reduce compression.
I actually have a BVM KVB 82 owners manual at home some place.. I’ll see if I can find it.
Ahhhhh back in the day. When it took real skill and patience to operate a jet.. Still love these engines
I used to run up to 20% in my Nelson/BVM engine. From what I can remember, you can go up to 20% nitro before you needed to add head shims to reduce compression.
I actually have a BVM KVB 82 owners manual at home some place.. I’ll see if I can find it.
Ahhhhh back in the day. When it took real skill and patience to operate a jet.. Still love these engines
05-24-2017, 03:19 AM
#3
My Feedback: (1)
I ran a KB 82 in a Byron Mig21, using the Byro fan and Byro Pipe. I ran K&B HP plugs and 30% heli fuel, motor ran great and put out 12lbs of thrust on a 9 1/2lb all up flying weight.
30% heli fuel has always worked for me in many setups including YS 120/140, Webra 25/32 and JETT .30/46. Never had to mess with head shimming and all my setupes where running tuned muffler pipes or Mousse Can Mufflers.
30% heli fuel has always worked for me in many setups including YS 120/140, Webra 25/32 and JETT .30/46. Never had to mess with head shimming and all my setupes where running tuned muffler pipes or Mousse Can Mufflers.
05-24-2017, 02:09 PM
#7
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Jeremy,
The recommended fuel for the K&B 72 DF engine was K&B 500 with a 12.5% nitro content. The oil was synthetic, X2C, which was a rebranded UCON MA 2270 product. When K&B got out of the fuel business BV had Pro Power blend 2 fuels for his DF engines, labeled JP4 and BV Special at 7% and 12.5% nitro content respectively. . JP4 was intended for humid and cold weather conditions while BV Special was for warm and dry conditions. Both blends contained a 23% oil content which actually aided cooling and provided a visible smoke trail for engine longevity. BV claimed that his engines actually went faster with the additional oil content. I used both with good results and actually blended the two for local weather conditions. Your stash of 15% nitro should be OK especially if you add oil to bring it up to 23%-castor oil preferred.
I strongly recommend that you use an after-run oil on completion of your DF flying sessions. Marvel Mystery Air Tool oil is my favorite but most any commercial model after-run would be fine. Remove the glowplug and add a healthy dose of after-run into the open port. Tilt the model nose-down and turn the engine over by hand using the starter probe. The goal is to get the oil seeped down to the front bearing. Insert the plug and hand tighten for storage. On your next flying session, remove the plug again and spin the engine over with the probe and your starter. Be sure to cover the plug port with a rag to avoid an after-run shower. Welcome back to glow DF and let us know how it all goes.
Rgds,
Art ARRO
The recommended fuel for the K&B 72 DF engine was K&B 500 with a 12.5% nitro content. The oil was synthetic, X2C, which was a rebranded UCON MA 2270 product. When K&B got out of the fuel business BV had Pro Power blend 2 fuels for his DF engines, labeled JP4 and BV Special at 7% and 12.5% nitro content respectively. . JP4 was intended for humid and cold weather conditions while BV Special was for warm and dry conditions. Both blends contained a 23% oil content which actually aided cooling and provided a visible smoke trail for engine longevity. BV claimed that his engines actually went faster with the additional oil content. I used both with good results and actually blended the two for local weather conditions. Your stash of 15% nitro should be OK especially if you add oil to bring it up to 23%-castor oil preferred.
I strongly recommend that you use an after-run oil on completion of your DF flying sessions. Marvel Mystery Air Tool oil is my favorite but most any commercial model after-run would be fine. Remove the glowplug and add a healthy dose of after-run into the open port. Tilt the model nose-down and turn the engine over by hand using the starter probe. The goal is to get the oil seeped down to the front bearing. Insert the plug and hand tighten for storage. On your next flying session, remove the plug again and spin the engine over with the probe and your starter. Be sure to cover the plug port with a rag to avoid an after-run shower. Welcome back to glow DF and let us know how it all goes.
Rgds,
Art ARRO
06-07-2017, 01:33 AM
#12
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Myles,
Yes I'm aware of Wolfe's adding turbine oil to glow fuel for DF use. However I would not advise doing so due to the hazardous nature of the unburnt fumes. Check the MDS data sheets on most of the turbine oils-really bad stuff with cumulative effects. Castor is a much safer alternative.
Rgds,
Art ARRO
Yes I'm aware of Wolfe's adding turbine oil to glow fuel for DF use. However I would not advise doing so due to the hazardous nature of the unburnt fumes. Check the MDS data sheets on most of the turbine oils-really bad stuff with cumulative effects. Castor is a much safer alternative.
Rgds,
Art ARRO
