rocket oil pumps

[TURBO200R4]

i opened this thread in response to steel and warps discussion on rocket wheelies causing lose of engine oil.
i started working on automatic transmissions in 1966 back in those days they had two pumps one of them being in the rear so that u could push start the vehicle. being that every auto trans has a pump i have worked on a lot of pumps since then so i would consider my self an expert.
for example an 89 ford when it is serviced by an untrained person they leave out the gasket on top of the filter. what happens is the car works perfect when going slow however when u give it some throttle the force of going forward causes the fluid to move to the rear of the trans causing the pump to suck air in to the pump and a second latter the car goes into a neutral condition. at this point the pump does not have pressure but there is still enough fluid on the bushings and thrust washers so no damage will occur.
my point being that just because u loose pressure for a couple of seconds there should be no damage.
i have studied the pumps in the rocket III. all the pumps i have dealt with are pumps that suck (in a good way) so having a tank higher than the pump is a good thing. it means that the pump is always primed and never starts dry. it sucks from a tank that is higher so easier to suck the oil.
as for the operation on the rocket the scavenger pump picks up oil from the back of the engine and pumps it in to the tank. if the rocket was standing straight up it would still pick up oil and return it to the tank.
the engine pump sucks oil from the center of the tank and because the tank is more than 1/2 full even if it was standing straight up it would still suck oil from the tank.
the only ways that it would starve for oil is maybe loose bolts on the pump, bad oil pressure relief valve or not there or something wrong that would exhaust the pressure. also if there was something wrong with the scavenging pump (loose bolts ect or system then the oil would not return to the tank so there would not be any oil it the tank for the engine pump to suck so it would be sucking air with 0 pressure and after a while a bad engine.

this is just my opinion and i welcome other opinions. because if they are real good opinions then i might change mine

 

[Joesmoe]

I don't have one -- I enjoy the discussion.

Back when I was flying aerobatics in a 1978 Decathlon 8KCAB (150 hp, CS prop, true inverted wing) we were told the plane was not true inverted, because it had high wings where the fuel was kept, so they put a 3 gallon header tank between the pilot's feet and simple gravity diverter valves so when the plane was turned inverted, those valves would move, allowing fuel to flow from the header tank, now above the engine, to the engine, but blocked from returning "down" to the wing tanks. The oil supply was similarly plumbed.

 

[rocketjohn]

I flew a C150....no aerobatics, but very docile stall that if you weren't expecting it could lift you off the seat for a brief moment. I did really steep turns...so much as the plane was capable, and never had fuel issues, or to my knowledge a lack of lube. My rocket....even though it IS a rocket, will remain horizontal and on two wheels so long as I am riding it.

 

[albertaduke]

I don't have one -- I enjoy the discussion.

Back when I was flying aerobatics in a 1978 Decathlon 8KCAB (150 hp, CS prop, true inverted wing) we were told the plane was not true inverted, because it had high wings where the fuel was kept, so they put a 3 gallon header tank between the pilot's feet and simple gravity diverter valves so when the plane was turned inverted, those valves would move, allowing fuel to flow from the header tank, now above the engine, to the engine, but blocked from returning "down" to the wing tanks. The oil supply was similarly plumbed.

Hey I also flew the decathlon in my early years and enjoyed it much, but were told not to remain inverted for more than seconds due to starvation was that 3 gls tank you mentioned FAA approved!

 

[warp9.9]

I wish I had a computer so I could point out the oil pathway thru the anti-leak down / also used as a one way valve when the engine is running thru the pump to the sump pan (yes the pressured oil also travels thru a port in the sump pan) before it enters the cross-over line that feeds the oil to the filter and then on thru the drillings that feed the main bearings and main bearing ladder the to the other pipe a routing. It is actually a maze. Ing. Not toention the scavenger pump has to seperate ports so if one of the sump pan screens does not have oil it can scaveng from the other without loosing suction. Not that the empty one won't scavenge a little along with the air. Lord help if both are not scavengine air with what oil the can. This is probably why they change the early sump pans suction ports which were dead center fore and aft to one starbord side and one port side fore and aft. Also lord hep you if the tank plug has 1 more thread yet still in tolerance and pushes the pan down a smigoen or the O ring does not reach the seating area so oil leaks thru the weep hole that there for when you draining the system. We wont get into whether tbe gasket deviding the two scavener ports is miss aligned so you suck extra air when one sump screen is out of the oil when your leaned over dragging the pegs. But since I have no computer maybe @Pedro can post some enlightenment pictures and thoughts for me and those who are curious. Man this smart phone sucks beer break

 

[warp9.9]

Oh ya those captains on the tech site like @Rocket Scientist or pedro , @Paul Bryant
Can go to my pictures and copy oil pathway 1 thru 10 and post it so we have something to help this discussion can feel free to. Make sure you get the discription with each picture to help us understand.

This was something Peter and I were hashing out trying to figure out why in some bikes can't keep oil in the tank for more then a day or do.

 

[BenchracerBob]

I don't have one -- I enjoy the discussion.

Back when I was flying aerobatics in a 1978 Decathlon 8KCAB (150 hp, CS prop, true inverted wing) we were told the plane was not true inverted, because it had high wings where the fuel was kept, so they put a 3 gallon header tank between the pilot's feet and simple gravity diverter valves so when the plane was turned inverted, those valves would move, allowing fuel to flow from the header tank, now above the engine, to the engine, but blocked from returning "down" to the wing tanks. The oil supply was similarly plumbed.

Quite a common solution that, indeed the mirage fighter had an inverted flight accumulater, I.e. another tank for inverted flight or negative Gs.

 

[Joesmoe]

@albertaduke The short answer is 'Yes'. That poor company had a tumultuous history. Under competitive pressure, still running steel, wood, and fabric, they made a number of changes right up to the end. In the end, there were about 40 employees, and they thought they could go on strike and get a better package, and the management said "We'll close". The workers decided to strike, and Bellanca was no more. The plane I flew was one of the last ones made by Bellanca. The CS prop and toe brakes were also "new" for that model, I was told (I don't know). Basically I flew it through the routines full throttle except on the down side of big loops, and in spins.

Those were single days, and women liked to ride in back, and didn't mind as I "had" to carefully adjust the five-point harness and chute.

Take off, reach 3k AGL level off, and let them know we had to "clean the floor" from the last messy passenger, and were they ready. Flip the plane inverted, inevitably hear the "whoop" of surprise, and notice all the dust falling from the floor. I never tired of that.

Had a triple whammy of getting married, moving away from the plane, and 9/11 restricting airspace, and gave it up. Looking around a few times, it became ever more difficult to find an FBO willing to rent the planes. The last time I went up in fact, they told me, "The plane is tired, and can't take wheel landings -- only tail landings please."

Good memories. Until I found the Rocket, that was "The most fun in daylight with your clothes on."

 

[Joesmoe]

Quite a common solution that, indeed the mirage fighter had an inverted flight accumulator, I.e. another tank for inverted flight or negative Gs.

While on the topic, my first job in the Air Force was working as a project manager in the F-16 program office, and with my aerobatic experience, I was surprised to learn the F-16 with all its sophistication for the time -- 9 G capability; look-down shoot down radar; ACE II ejection seat; it was NOT designed to go inverted. I asked a number of pilots about that, and they said "we don't like to fly inverted -- with a 720o/sec roll rate (clean -- half that dirty) it's easier to roll and pull. When they had that disaster with the Thunderbirds during training with the T-38 where a bunch of them flew into the desert when the lead's elevator jammed, the order came down to us to prepare eight F-16s for T-Bird duty. With world-wide duty, they weren't allowed to be war planes, so we were required to have the fire control radar and gun removed in such a way the planes could be returned to combat configuration within 72 hours. So we put a lead plate in the nose in place of the radar, and a filet to cover the gun port. The more interesting test program was to instrument one of our test planes and fly it inverted to see what happened. The oil system was the only issue, and it simply wasn't practical to redesign that. So we asked the T-Bird folks what is the longest they would be inverted, and found out how much pressure was generated in the oil system during that time, and fitted those eight planes with a larger gauge accumulator tank (the weak link) to withstand the maximum expected pressure, and that's how they fly to this day, thirty-four years later.

 

[albertaduke]

While on the topic, my first job in the Air Force was working as a project manager in the F-16 program office, and with my aerobatic experience, I was surprised to learn the F-16 with all its sophistication for the time -- 9 G capability; look-down shoot down radar; ACE II ejection seat; it was NOT designed to go inverted. I asked a number of pilots about that, and they said "we don't like to fly inverted -- with a 720o/sec roll rate (clean -- half that dirty) it's easier to roll and pull. When they had that disaster with the Thunderbirds during training with the T-38 where a bunch of them flew into the desert when the lead's elevator jammed, the order came down to us to prepare eight F-16s for T-Bird duty. With world-wide duty, they weren't allowed to be war planes, so we were required to have the fire control radar and gun removed in such a way the planes could be returned to combat configuration within 72 hours. So we put a lead plate in the nose in place of the radar, and a filet to cover the gun port. The more interesting test program was to instrument one of our test planes and fly it inverted to see what happened. The oil system was the only issue, and it simply wasn't practical to redesign that. So we asked the T-Bird folks what is the longest they would be inverted, and found out how much pressure was generated in the oil system during that time, and fitted those eight planes with a larger gauge accumulator tank (the weak link) to withstand the maximum expected pressure, and that's how they fly to this day, thirty-four years later.

how sometimes the answer to a problem can be simple yet effective and long lasting .BTW when I flew the decathlon i always flew solo in the rear seat , if a pax was to ride he would be in the front seat yet all controls were dual ,
like you those were the days....