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Go-Around Pitch Attitude

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Chucker

Well-Known Member
Supporting Member
Joined
Nov 1, 2013
Messages
894
Location
Prescott Valley
I need to check my fuel flow rate at maximum takeoff pitch plus 5 degrees. Is it safe to assume that a 75-80 HP Sonerai at minimum weight does not get the nose any higher than 10-12 degrees in a normal go-around climb?

Thanks,
Chucker
 
I don't have a photo to prove it but my S2 LS with the Jabiru 125 hp engine when climbed at 75 mph has the nose up at 45 degrees or higher.
True if I want to keep the valve seats in place, once is all I want to do that. Test Flight.
At 85 or 95 mph the climb angle is much less. Cruise climb at 115 is maybe 5 fpm.
Bil438
 
Hey Chucker, I almost always do a shallow climb to keep good airflow through the cylinders. I like to accelerate to 120 mph IAS then pull the nose up to what I would guess is about 12 degrees, seldom have it very nose high at all, then I probably see close to 1000 fpm...I'm guessing again (S-1).

Prior to the first flight to measure fuel flow I put the tail in a ditch, had about 20 degrees of pitch, had about half fuel (5 gal) and flowed about 13 gph. Then while in the ditch I ran it wide open for about two minutes. No issues. That is with a Revflow slide carb.

Best Wishes,
Kevin
 
You got me thinking ref. useful data.

- I can maintain level flight and about 110 mph indicated at 2500 rpm if need be to limp home. Never had to.

- My stall is at 60 mph indicated. I fly downwind at 100 mph IAS, base at 90 mph IAS, final at 85 and cross numbers at 80 mph.

- I have no idea what airspeed I lift off at. I raise tail fairly early, set a takeoff attitude and just let it fly off...when ready.

- All my landings are three point. If I cross numbers at less than 80 mph IAS I will touch tail first, I don’t like that. That is a factor of having a 4 inch API tail wheel, not a big deal.

- S-1 is touchy on roll out. I suspect S-2 being longer, not so much.

- Be sure to install a “ball” i.e. slip skid indicator.

- Not a problem but my stock height vertical stab is not enough.

- My standard small rudder is very effective.

- I never manage to fly the machine for a full hour but just playing around locally my fuel burn seems to be @ 4 gph.

- I’ve got 40 hrs on the machine, 2180 GPAS, never have run anything except 100LL.

Airplane is fun to fly!

Kevin

-
 
Thanks, Kevin

Retirement rocks! I’ve been busier than a one-armed paper hanger. Don’t know how I ever had time for UPS.

Great data points. I’m hoping that the longer fuselage of my II minus will help on the runway and give the stock tail enough authority airborne. Also hope your hat the streamlined canopy will improve the authority of the tail and rudder. We’ll see.

All the best,
Chucker
 
I'm using 1/4 inch line and a 1/4 inch inline fuel filter from Jegs. The filter is their metal filter that uses a replaceable metal cartridge designed for motorcycle application.

I know it seems like a stretch to flow up to 15 gph through a 1/4 inch line but I went back and looked at my build notes and am sure that is an accurate number. The S-1 has a pretty reasonable amount of head pressure as the tank sits pretty high up on the fuselage longerons.

Kevin
 
Chucker,
Like Kevin I too used 1/4 Aluminm fuel line. I ran it from a Automotive fuel filter to a Facet boost pump on the firewall. I used a firewall through fitting to firesleeved aeroquip to the carb.
Despite having great head pressure with the nose tank and my carb being at the lowest point under the cowl, I still utilized a boost pump on takeoff/landing or flying below 1000’ AGL.
I Ops tested high AOA/ Full throttle climbs BP on and off and never got a sputter, even straight vertical. Normal go around or takeoff/climb profiles at 90mph shouldn’t exceed 15 degrees.
** Texas heat notwithstanding, vapor lock is always a concern with a tightly cowled engine, as 25 years of RVs taught me. For me, a boost pump is worth installing.

V/R
Smokey
 
I ran 3/8 aluminum fuel line all the way to the filtered gascolater then 1/4 out of the gascolater to the aero carb. My original test was with the airplane on a 30 degree hill tail low. 1/2 gallon of gas, wide open for 5 minutes, no issues whatsoever. In fact the only time the engine ever quit was when it was running outside the hangar for awhile while I was messing around with things in the cockpit and it just died. When I pulled the line from the bottom of the tank there was zero fuel left in the tank.
 
Yes I would think that 10-12 degrees makes sense. If you do any sport flying or aerobatics, you'll exceed that. I run a facet pump and suggest one for you. Too much is at stake if your calculation is wrong.
BillE
 
I’ve only seen them used on two cycles like two cycle Rotax. The four cycle Rotax 912 for example uses a mechanical pump.

Just to be clear, I have no fuel pump on my 2180 GPAS, agree every installation is different. I have very little fuel line FWF in an effort to avoid vaporlock. I also exclusively use 100LL for same reason.

Kevin
 
i only use a fuel line thru the firewall thru a fuel filter and into the revflow carb. no issues at all
 
FWIW my fuel filter is on the cold side of the firewall and therefore I probably have four inches of fuel line on the engine side and it is firesleeved.

I do have a last chance low point drain at the firewall per Fred's suggestion, very small, made out of half inch aluminum bar stock with a typical spring loaded fuel drain on the bottom.

Like BoeingPilot I am running a Revflow and it is fine.

Kevin
 
I've run both the mechanical pumps that comes with Jabiru engines and a facet 3.5 which is a pulse pump.
But both caused flooding below 2000 rpm, so I've gone to a 0-2.0 psi facet pump. Won't know til spring.
BillE

quote author=Chucker link=topic=4637.msg35274#msg35274 date=1546483385]
...all this talk about fuel pumps....

Has anyone experimented with pulse/vacuum type fuel pumps?
[/quote]
 
I thought about using a fuel pump (possibly a pulse pump) with a return line to the top of the fuel tank. In that configuration the fuel pressure would always equal the head pressure of a full tank.

Thoughts?
 
I’ve been flying my airplane forever (32+ years) with NO fuel pump in the primary fuel system (I do have a Facet fuel transfer pump between the aux tank and the main tank). It’s not necessary if you mount the carb under the engine. Gravity never fails.
 
Thanks, Fred

I'm actually just tossing ideas around.... I don't have a pump and don't plan to add one. Many options, however, have crossed my mind. Gravity is a given.

On the vapor lock issue, my filter and plumbing are on the cold side of the firewall. The line to the throttle body is direct and I plan to protect it with fire sleeve.

While I have you.... what is your opinion on the proper nose up attitude for the fuel flow test? I am using 5/16" plumbing and don't have trouble getting 10 gallon per hour flow.... but I need to find my usable fuel low level.

All the best,
Chucker
 
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