Giants From South Africa

[damien]

	Quote: Originally Posted by saflyer
	Hook it to the back of your car and use it as a trailer.

Lol! I just pictured that in my head, it could almost work and if you put some indicators and brake lights on, then it would be road legal.

[pe reivers]

Gary, looks good.
Look at post 4910 again, especially the little brass tube on top of the fuselage. It is hooked up to the carb regulating membrane cover and provides a constant reference pressure for mixture control.

[saflyer]

Gary, that sounds like fun.

I've seen that happen with a H9 Extra 260. The guy was stupid enough to put in a MVVS 58. I told him that the plane is too small for such a powerful engine and that he will have to be very careful with his trottle.

Did he listen, na. On take off he went full throttle and the plane was left behind. The cowl got ripped out and the engine landed about 10m infront of the plane. He never came to the field again.

[flight_stick]

	Quote: Originally Posted by arnobergmann
	That's almost like the 116 mount on the 35%H9 Extra. Looking good Gary. I'll post some pics of the Waco later, just need to resize them.

The motor a very slightly bigger in width than the 116 , smaller than the 3w 150 and lighter than the 3w and DA 150..

[flight_stick]

	Quote: Originally Posted by pe reivers
	Gary, looks good. Look at post 4910 again, especially the little brass tube on top of the fuselage. It is hooked up to the carb regulating membrane cover and provides a constant reference pressure for mixture control.

PE I was wondering what that tube was. Does it have to be on the outside? Can it be inside the cowl, connected to the Carb? Also how far into the fuzz do you run the brass tube? All these questions.

I must try that on the 116. I have it in an Extra 260 , every time the aircraft goes inverted , motor riches up. Would that help?

[saflyer]

Guys who is up for some flying on Tuesday the 16th.
You are all welcome to fly at PRF. Bring your LS or what ever fits into your car and come down and enjoy a couple of hours in the sun.

Peter

[Borries]

	Quote: Originally Posted by RV-8
	Here are some pics of the Comparf Extra 260, I finished it in April a Day before the Large scale nats and flew it in Intermediate. Managed a 3rd place with a overall percentage in the 70s and an upgrade to Expert. The DLE 110 instalation is almost finished, cant wait to get back to some IMAC practise.

Nice Plane
BB

[flight_stick]

Ok Thats the motor mounted. Tomorrow need to finish the throttle and choke linkages. Install new tanks with plumbing and Ignition. Hopefully Friday I get to run the beast.

[bluesmancoops]

	Quote: Originally Posted by arnobergmann
	That's almost like the 116 mount on the 35%H9 Extra. Looking good Gary. I'll post some pics of the Waco later, just need to resize them.

do you have a Waco now?

[arnobergmann]

	Quote: Originally Posted by bluesmancoops
	do you have a Waco now?

No i'm building one for a friend. AMR kit (40%) with Moki 250cc radial.

[pe reivers]

	Quote: Originally Posted by flight_stick
	PE I was wondering what that tube was. Does it have to be on the outside? Can it be inside the cowl, connected to the Carb? Also how far into the fuzz do you run the brass tube? All these questions. I must try that on the 116. I have it in an Extra 260 , every time the aircraft goes inverted , motor riches up. Would that help?

It should solve inverted flight problems, unless the membrane weight is enough to upset the mixture. In that case, a slight needle adjustment will solve the issue.

That tube is part of a system also known as Prandtl tube or pitot tube, and The static part (not the pitot part) provides a constant static pressure if pointing straight into the free flowing airstream. That is just what is needed for a constant carb mixture. Inside the fus it is of no use, because then it will measure the pressure inside the fus, which is no good and causes all kinds of problems. I have described it in detail on my forum under "teaching the walbro to fly"
The length of the tube is not critical, and we had success with tubes as short as 2.5cm (1" ), positioned in a straight airflow path, and about 1.5cm outside the fuselage wall. propeller turbulence does not seem to upset the device.

The device is used in speed sensors, but also in altitude meters
From NASA pages http://www.grc.nasa.gov/WWW/K-12/airplane/pitot.html I quote:
Pitot-Static tubes, which are also called Prandtl tubes, are used on aircraft as speedometers. The actual tube on the aircraft is around 10 inches (25 centimeters) long with a 1/2 inch (1 centimeter) diameter. Several small holes are drilled around the outside of the tube and a center hole is drilled down the axis of the tube. The outside holes are connected to one side of a device called a pressure transducer. The center hole in the tube is kept separate from the outside holes and is connected to the other side of the transducer. The transducer measures the difference in pressure in the two groups of tubes by measuring the strain in a thin element using an electronic strain gauge. The pitot-static tube is mounted on the aircraft so that the center tube is always pointed in the direction of travel and the outside holes are perpendicular to the center tube. On some airplanes the pitot-static tube is put on a longer boom sticking out of the nose of the plane or the wing.
Difference in Static and Total Pressure
Since the outside holes (in the static tube part) are perpendicular to the direction of travel, these tubes are pressurized by the local random component of the air velocity. The pressure in these tubes is the static pressure (ps) discussed in Bernoulli's equation. The center tube (Pitot part), however, is pointed in the direction of travel and is pressurized by both the random and the ordered air velocity. The pressure in this tube is the total pressure (pt) discussed in Bernoulli's equation. The pressure transducer measures the difference in total and static pressure which is the dynamic pressure q.

[flight_stick]

Ok Guys, thread is dead again. Here are some pics, motor installed, cowl and spinner cut and fitted. All linkages done, plumbing done. Tomorrow will be fitting exhausts and doing final fit for bottom of cowl

[pe reivers]

Pls don't forget to put in the cooling baffles and hot air extraction?

[flight_stick]

	Quote: Originally Posted by pe reivers
	Pls don't forget to put in the cooling baffles and hot air extraction?

Pe, thanks.I have done that already, attached 2 picture. That lips as you know under the cowl causes a change in pressure( low pressure zone) so hopefully all that hot air will be pulled out.
Let me know what you think. Unfortunately not going to get it finished before I leave back to work, so will just have to wait. Have a lot of work to do on the cowl still before its ready to be sprayed. Will measure the distance from engine exhaust manifold to entrance in fuzz for canister. Basically all we need it the height. How does the manifold connect to canisters, with flexible steel hose or silicone tube?

[pe reivers]

Gary, I think it will work OK if you close those long slits in front of the wind dam, and add louvres in the large opening to support he wind dam function. The last louvre should overlap the fuselage front slightly. The rim that is there now will destroy air extracting function and cause the airflow to enter the cowl again, thus creating a high pressure zone. Just the opposite of wat you want to achieve.

PS
You also can put a set of louvres in the opening as it is now, including the long slits.