Waiters 2nd First Flight

[Waiter]

Looks like I have a pretty good leak in the Pitot system.

 

When I pump it up to about 160 kts, it drops dow to 150 in about 2 seconds. (Standard should be no more than 10 kts in one minute)

 

The leak seems to be in the nose cone. I have a 5/16 stainless Pitot tube that fits over the original aluminum one. I bet money this is where the leak is. I'll look at it some more tonight.

 

ALSO ; Not 100% sure, but my static lines may also have been plugged. Anyway, I redrilled all six of them (standard location under the canard, 3 on each side of the plane).

 

Waiter

[Waiter]

Fixed the major leak, still seem to have a small leak.

 

Also need to reshim the left wing (still high AOA)

 

And, I have a gear door that sounds like its fluttering (buzzing at about 165kts). Need to realligh gear doors.

 

I ordered a new battery, and my Alternator needs to be replaced (light stays on dim, probably a bad diode)

 

SPEED --

 

 

To date, I have 165kts at full throttle (2300 RPM) , sea level, straight and level.

 

This is about 5 kts faster than when I started. This is not a final number, I suspect when I get my Pitot leak taken care of, and reshim the left wing, this will improve (I hope).

 

Also, I'm going to temporarly replumb my old original airspeed indicator to see if there is a discrepancy between the Dynon and the original Airspeed indicator.

 

Waiter

[TMann]

And, I have a gear door that sounds like its fluttering (buzzing at about 165kts). Need to realligh gear doors.

 

Waiter, were you able to isolate the gear door problem?

Was is just a tension issue?

[Waiter]

I increased the UP pressure to 900 psi. No more gear door noise.

 

I need to put the plane on jacks and do a retract just to double check the alignment.

 

ALSO -

 

I did a series of speed runs up to FL180. I need to reconnect my old original airspeed guage to see if there is a difference in calibration between the Dynon and the original.

 

The airspeeds I seen were almost identical to what they before I made any modifications. So I'm looking for explainations for this.

 

Waiter

[Lynn Erickson]

 

The airspeeds I seen were almost identical to what they before I made any modifications. So I'm looking for explainations for this.

 

Waiter

Thats the same thing that John Graves said after he had Steve Drybread put in the retracts. he spent $ 15,000 and said he had to look very hard at the airspeed indicator to find 5 knots of increase. After all the great work you did on yours I hope you do find more speed then that.

[JLKnolla]

Keep in mind that there are many things going and multiple changes all introduced simultaneously any one of which could not yet be optimal (DD cooling is my best guess at a culprit). I know Waiter knows this, just saying that there are I bet many little things that will present themselves and be fixed. Key at this point I think is to make one fix at a time, e.g., oil cooler inlet/exhaust, then DD inlet and plenums, then maybe a flowguide for spinner, etc. Don't forget prop settings too (coarse pitch stop, etc.)

 

Glad it is flying OK, I am confident Waiter will track it all down.

[TMann]

Wasn't the prop one of the new features of the retrofit?

I would not suspect the DD cooling as a big drag issue.

[Lynn Erickson]

Wasn't the prop one of the new features of the retrofit?

I would not suspect the DD cooling as a big drag issue.

No, I believe had been flying with the CS prop for some time before these mods. I know he had it when he did the lower winglet removal mod, that did very little for speed. DD cooling should be less drag unless he has more inlet then he needs.

Most of all the speed mods have a much bigger effect at low altitudes where most ez's don't fly much. from a clean stock plans ez to a full race clean machine , if you see 10 knots at low altitude you are doing go. the biggest differences are good wheel pants and the right prop for the altitude that you want to go fastest at.

[TMann]

Same prop and engine.

Yeah .... you are right Lynn. I found it on the post where he talked about his weight and balance.

[Edge 513]

Well I think Waiters plane is plain cool lookin' even if it is just about as fast as before.

Good on ya John!!! Classy and Snarky to the max!

[JLKnolla]

For the record, I'm not suggesting DD in theory is more draggy, just saying that the difference between what is calculated vs. what the real world needs may yet result in some changes specific to Waiter's plane. Look at Wayne Blackler's or Bill James' NACA style DD inlets and compare them, spillage drag can be significant, especially for an otherwise very clean plane.

 

Not making any criticism of Waiter's design BTW, just saying that DD cooling is a significant change from the baseline and that inlet area, plenum design, exhaust area, etc., will all contribute to whether it works or not, and if so, how well or not.

 

This is why we call it EXPERIMENTAL aviation. I remain confiddent Waiter will get it all figured out.

[Lynn Erickson]

For the record, I'm not suggesting DD in theory is more draggy, just saying that the difference between what is calculated vs. what the real world needs may yet result in some changes specific to Waiter's plane. Look at Wayne Blackler's or Bill James' NACA style DD inlets and compare them, spillage drag can be significant, especially for an otherwise very clean plane.

 

Not making any criticism of Waiter's design BTW, just saying that DD cooling is a significant change from the baseline and that inlet area, plenum design, exhaust area, etc., will all contribute to whether it works or not, and if so, how well or not.

 

This is why we call it EXPERIMENTAL aviation. I remain confiddent Waiter will get it all figured out.

your right, one of the hardest things to do is get the inlet right on the first try. if we had a wind tunnel it would be simple but most don't. you need to build it and then if, it cools ok, start decreasing it's size until it effects the cooling and then you know where the size limit is. most that are doing the DD inlets are using imfo from the last guy who said his works. if you build them for max speed then they may be to small for a long climb. most of problems with the inlets are related to spill over or back flow usually cause by too large of an inlet and the air backs up and keeps air from entering. bigger is not always better. the stock NACA inlet on the bottom suffers from this, a lot of spill over on the sides that causes loss of cooling air and drag

[longez360]

Modifications that show up on one's airspeed indicator are very, very rare and perhaps not detectable unless you have quality comparable baseline data. There are few people in the EZ world who are realists when it comes to drag reduction - They conduct accurate flight tests, and achieve and record usable flight test data (Savier, Hertzler).

 

Inlet sizing and location requires flight test atmospheric data acquisition and quantification of the actual requirement. That requirement needs definition as well as quantification (eg. What do you need? worst case requirement? lowest drag? operational environment inputs are? Flight profile is?). Stoichiometry helps in quantification (induction) - How much air do you need to burn fuel? There are reports out there on how to size a duct for air mass flow. Lycoming states the pressure drop requirement for cooling each of their engines. Stewart Warner publishes the data for oil coolers.

 

Anything other than some considered calculations based on said data will give erronous results, or hey, luck might get you there...

 

If in doubt, revert to the fundamental laws of physics. They will always get you there.

[Waiter]

COOLING

 

My cooling intakes are approximately 14 sq inches on each side. Each intake feeds its own plenum.

 

The Cylinders are fairly well sealed against leaks.

 

CHTs are all within 25 deg of each other. With 90 deg OAT, I'm seeing 400-425 CHT on a high power, low speed, climb.

 

At full power cruise, CHTs are hanging between 350 - 375.

 

My intakes are a little to large, 10 - 12 inches would probably be OK. Latter, if I feel like it, I may make some temporary lips that I can tape to the intakes to close them down a little, but not now

 

COMBUSTION AIR

 

 

I'm currently getting my combustion air from inside the lower cowl (hot area). This could easily rob me of 10-15 hp

 

When I built my cowl, I installed small (5 sq inches) armpit scoops on each side of the cowl. The left scoop is ducted and plumbed for the Oil Cooler. The right scoop is meant to be used for unfiltered combustion air.

 

This weekend I'll build the ducting to route the air from the scoop, down the side and bottom of the cowl, then into a small plenium box where the air needs to turn 180 degrees then enter into the engine air intake.

 

Waiter

[Waiter]

I just published a short report on my web site regarding the performance after the retrofit.

 

http://www.iflyez.com/LongEZRetrofitReport.shtml

 

I want to thank LimoEZ for the photos he took at the pancake breakfast at Port Clinton.

 

Waiter

[Lynn Erickson]

I just published a short rreport on my web site regarding th eperformance after the retrofit.

 

http://www.iflyez.com/LongEZRetrofitReport.shtml

 

I want to thank LimoEZ for the photos he took at the pancake breakfast at Port Clinton.

 

Waiter

I would like to see the chart of the speeds in the cruse altitudes, like 11,000 to 12,000 feet. if you got 10 kts at 2500 ft and 2 kts at 18,000 ft the speed increase at 12,000 ft should be about 5 kts. that would be inline with what John Graves and Steve Drybread were getting with the Drybread retracts. soon the Chino Aero canard will fly again without the retracts and we should see the same difference in speed with the fixed gear. only about 5 kts slower but will never have to wonder if the mains are going to be there every time we want to land.

[TMann]

....only about 5 kts slower but will never have to wonder if the mains are going to be there every time we want to land.

??? was there a time where it wasn't?

[Lynn Erickson]

??? was there a time where it wasn't?

Yes when it had the not even dependable infinity retracts. which are gone now, in favor of the stock gear bow. we got rid of the old gear and that over sized infinity stick grip.

[TMann]

Yes when it had the not even dependable infinity retracts. which are gone now, in favor of the stock gear bow. we got rid of the old gear and that over sized infinity stick grip.

ha, ha, haaaaa ....... so there is extra room in the cockpit as well, eh?

 

You should start a thread about that.

 

Waiter ..... great info. You've done some great work there and your contributions are much appreciated.

[Waiter]

The 10 kts can be attributed to a combination of drag reduction retrofits;

 

The retractable main gear, downdraft cooling, and nose gear doors are the three main reduction items.

 

Waiter

[Firefly-YCTTSFM]

Waiter, if you don't mind me asking, how did you maintain currency during the 4 1/2 years of the rebuild? Also, did you do any specific proficency "warm-up" to prepare for flight test (borrow a RV-8 for a few hours?).

 

PS everybody: I've already heard the "you'll save lots of currency not flying" joke...

[Waiter]

how did you maintain currency during the 4 1/2 years of the rebuild?

Poorly, A couple hours a month in a worn out, underpowered, C-172. :sad:

 

I'm a little rusty, and my reactions/thinking is a little slower. Its getting better now that "I'm back in the Saddle Again":cool:

 

Waiter