RAM 500 Problems-Solutions?
09-12-2005 | 06:54 PM
#1
Thread Starter
My Feedback: (2)
RAM 500 Problems-Solutions?
RAM 500 NOTES
After going through a lot of problems with my RAM 500, I thought my experiences might help others. I found there are a lot of simple things you can do to maintain your engine.
My engine (SN 113) never ran right from the start and I had to send it for repairs after RAM went out of business. The fuel manifold was replaced and shims were added to bring it to factory specs. After the repair the engine was shipped to my son in Arlington, Tx. There it was successfully flown in two airplanes. The last 13 flights were in my new Boomerang Intro. It was then shipped to Denver where I live and I think it has achieved the βRunβ condition only once since arriving in Denver in approx. 30 attempts.
Besides the run problems I also had a starter problem. Currently I have adapted the new larger bendix to the old mount. I had to make a spacer ring to space the starter motor back to accommodate the longer bendix. It motor still fits in the original motor cover.
I finally decided to disassemble the engine my self. First I started to remove the exhaust nozzle and found most of the screws to only be hand tight. There was a lot of black carbon area around the case where the nozzle mates to the case. It was obviously leaking a lot.
Next I pressed the motor assembly out of the case. There is a large βOβ ring that seals the case to the diffuser assembly. This βOβ ring was leaking approx 1/3 of its diameter. I found a Viton βOβ ring that was a perfect fit. I reassembled the engine and it still would not run.
I became suspicious of my fuel pump so I hooked my engine to another fuel pump, ECU and battery that was working good with a different RAM 500 engine. I made three attempts and once it went to 51K RPM and then stopped suddenly with a lot of flame out the back. The other two attempts would not light the kero.
At this point I was suspicious that I had plugged fuel needles. I disassembled again and this time I removed the nut holding the compressor on and then the shaft with turbine wheel slid out the back of the engine. Next I was going to remove the NGV and discovered 3 of the 4 screws were only finger tight. The forth took a slight twist with the hex wrench to move it. I donβt see any damage from the screws being loose. After removing the screws it was now possible to slide the combustion chamber off the back of the assembly. Visual exam revealed a lot of carbon build up on the inside of the combustion chamber front plate. Testing showed that the inside dia. of the fuel needles is .020 dia. so a piece of music wire was used to test for clogged needles and two were completely closed off and 3-4 more were partially clogged. Next I hooked a PowerMax bottle to the fuel in line and using a shutoff value turned on a small about of gas and lit the needles I now have a good even length of flame from each needle.
Next I decided to do a fuel flow test through the needles. I used a hookup where I could hook one nicad cell directly to the fuel pump and could also hook two nicad cells in series to the pump. Using my pump and one nicad cell gave a very small fuel flow with the assembly held so that the needles were all at approx. a 45 degree angle from vertical. I did not see much fuel coming out of the needles but it did drip off each needle. Next I hooked up the two nicads in series to the pump and the needles sprayed fuel out the ends about 1β long. Next I tried the second pump and with one nicad cell the stream was 1/8β long and with two nicad cells it was about 2 to 2 Β½β long. The difference between the two pumps is dramatic.
On the RAM 500 there are three small stainless tubes the go through the diffuser, one for fuel, one for starting gas and one for lube fuel to the bearings. A 1mm x 1mm βOβ ring is compressed around each of these tubes when you tighten the fittings that hold the external tubes to the diffuser. The stainless tubes are a very loose fit in the βOβ ring even when the fittings are fully tight. I added a second 1.5mm x 1.5mm βOβ ring on top the exiting one. I used this setup when I did the fuel flow tests and did not have any leaking. My engine has been continually wet on the front side of the diffuser and I think those fittings have been leaking.
In summary I would check the tightness of the exhaust nozzle screws about every 10 flights (we found loose screws on 3 other engines) until they prove they will stay tight. If you have to remove the front cover for anything check to see that the front of the diffuser is dry. If not your fittings are probably leaking. After I have run my engine for awhile I will know if adding the 1.5mm βOβ is a good solution.
After going through a lot of problems with my RAM 500, I thought my experiences might help others. I found there are a lot of simple things you can do to maintain your engine.
My engine (SN 113) never ran right from the start and I had to send it for repairs after RAM went out of business. The fuel manifold was replaced and shims were added to bring it to factory specs. After the repair the engine was shipped to my son in Arlington, Tx. There it was successfully flown in two airplanes. The last 13 flights were in my new Boomerang Intro. It was then shipped to Denver where I live and I think it has achieved the βRunβ condition only once since arriving in Denver in approx. 30 attempts.
Besides the run problems I also had a starter problem. Currently I have adapted the new larger bendix to the old mount. I had to make a spacer ring to space the starter motor back to accommodate the longer bendix. It motor still fits in the original motor cover.
I finally decided to disassemble the engine my self. First I started to remove the exhaust nozzle and found most of the screws to only be hand tight. There was a lot of black carbon area around the case where the nozzle mates to the case. It was obviously leaking a lot.
Next I pressed the motor assembly out of the case. There is a large βOβ ring that seals the case to the diffuser assembly. This βOβ ring was leaking approx 1/3 of its diameter. I found a Viton βOβ ring that was a perfect fit. I reassembled the engine and it still would not run.
I became suspicious of my fuel pump so I hooked my engine to another fuel pump, ECU and battery that was working good with a different RAM 500 engine. I made three attempts and once it went to 51K RPM and then stopped suddenly with a lot of flame out the back. The other two attempts would not light the kero.
At this point I was suspicious that I had plugged fuel needles. I disassembled again and this time I removed the nut holding the compressor on and then the shaft with turbine wheel slid out the back of the engine. Next I was going to remove the NGV and discovered 3 of the 4 screws were only finger tight. The forth took a slight twist with the hex wrench to move it. I donβt see any damage from the screws being loose. After removing the screws it was now possible to slide the combustion chamber off the back of the assembly. Visual exam revealed a lot of carbon build up on the inside of the combustion chamber front plate. Testing showed that the inside dia. of the fuel needles is .020 dia. so a piece of music wire was used to test for clogged needles and two were completely closed off and 3-4 more were partially clogged. Next I hooked a PowerMax bottle to the fuel in line and using a shutoff value turned on a small about of gas and lit the needles I now have a good even length of flame from each needle.
Next I decided to do a fuel flow test through the needles. I used a hookup where I could hook one nicad cell directly to the fuel pump and could also hook two nicad cells in series to the pump. Using my pump and one nicad cell gave a very small fuel flow with the assembly held so that the needles were all at approx. a 45 degree angle from vertical. I did not see much fuel coming out of the needles but it did drip off each needle. Next I hooked up the two nicads in series to the pump and the needles sprayed fuel out the ends about 1β long. Next I tried the second pump and with one nicad cell the stream was 1/8β long and with two nicad cells it was about 2 to 2 Β½β long. The difference between the two pumps is dramatic.
On the RAM 500 there are three small stainless tubes the go through the diffuser, one for fuel, one for starting gas and one for lube fuel to the bearings. A 1mm x 1mm βOβ ring is compressed around each of these tubes when you tighten the fittings that hold the external tubes to the diffuser. The stainless tubes are a very loose fit in the βOβ ring even when the fittings are fully tight. I added a second 1.5mm x 1.5mm βOβ ring on top the exiting one. I used this setup when I did the fuel flow tests and did not have any leaking. My engine has been continually wet on the front side of the diffuser and I think those fittings have been leaking.
In summary I would check the tightness of the exhaust nozzle screws about every 10 flights (we found loose screws on 3 other engines) until they prove they will stay tight. If you have to remove the front cover for anything check to see that the front of the diffuser is dry. If not your fittings are probably leaking. After I have run my engine for awhile I will know if adding the 1.5mm βOβ is a good solution.
09-12-2005 | 08:20 PM
#2
RE: RAM 500 Problems-Solutions?
I also have a Ram500 my engine gave me problems to. I had replced the starter motor with speed 300, I also had to replace the fuel pump. My engine would throw flame around 70-80k rpms. The fuel pump seemed to stall then speed or maybe the gear was slipping. I once removed all the electronics from the eng and submerged the eng in degressor 409 cleaner. Back flushed the fuel line, blow air though the eng. Reinstalled electronics and lube the bearings. When I started the eng my full speed PWM was 525 at 150k. Finally the best for last, I replaced the ram fuel pump again same problem this time I used a AMT Mercury pump. First I adjusted My start PWM to 75-80 next I adjust my propane to 50. I also switch to propane not powermax. My eng starts smoother and my full power PWM is 325 at 150k. My idle to full power takes 3-4sec .
09-13-2005 | 09:40 AM
#4
My Feedback: (49)
RE: RAM 500 Problems-Solutions?
"Next I was going to remove the NGV and discovered 3 of the 4 screws were only finger tight. The
forth took a slight twist with the hex wrench to move it. I donβt see any damage from the screws
being loose."
My Ram 500 seized in flight last week because those screws came loose. Now I'm faced with an expensive repair bill. I'd suggest that Ram 500 owners check out their engines and put locktite on the NGV to bearing tunnel screws.
Joe
forth took a slight twist with the hex wrench to move it. I donβt see any damage from the screws
being loose."
My Ram 500 seized in flight last week because those screws came loose. Now I'm faced with an expensive repair bill. I'd suggest that Ram 500 owners check out their engines and put locktite on the NGV to bearing tunnel screws.
Joe
