Before Evan came today I 🙂 !!!!! did 1 full length runway taxi (on the taxi way).
Evan did another 3 fast taxis on the long runway at NZRT today, see video below:
Basically he says the mixture is still to rich, mainly at the full throttle position. The engine gets up to the speed that the propeller is designed for, but its not enough power or torque to get the Bleriot off the ground…….. So I don’t know, just little steps now.
So I will start looking into maybe modifying the jet’s inside the carburetor to improve this.
And yes today I installed the carburetor again onto the engine.
Yes it looks to work just fine!!!!
There is one interesting initially a bit confusing feature though.
During the throttle range from 0% to 80% or so, you need to adjust the mixture control, like you would expect. More air, more fuel.
But at the highest throttle setting, the carburetor opens a second channel, see diagram below, and suddenly leaning of the mixture hardly does a thing. Like its not killing the engine, but you still hear it revving up a bit from 1500 to 1600rpm.
The acceleration pump is controlled by the throttle, and when the throttle is open very quick, extra fuel is “pumped” into the main discharge nozzle and into the air stream.
But when just opening the throttle slowly or at any speed really, the pump piston with the two pins on top (see diagram) gets pushed down, opening a hole you can’t see on this diagram, allowing extra fuel into the main discharge nozzle.
So yes, the initially confusing behavior is correct. But because I still need to lean of the mixture all the way to 0%, maybe I need to get a smaller jet, the left one.
Now reading the carburetor findings from Wed 9 Jul 2014, I noticed that the fuel pump jet is already smaller then what’s on the id plate on the carburetor. I wonder if the previous owner has been “playing” with this to get full throttle mixture rating correct.
From what I see here it looks like that jet is still a bit to big.
I will have to talk to some people about this !!!!
BUT LOOKING GOOD NOW.
So after my initial engine testing, I started taxing the Bleriot. Went up and down the taxiway twice. All went really well. Could steer really well !!!!
When I came back I did another engine test, and it still goes to 1600rpm. Total engine time was 0.9 hour.
Because I am running the engine a lot leaner then before, the spark plugs aren’t “flooding” anymore, and because of that the engine runs on all 5 cylinders now.
SO READY FOR THE NEXT FAST TAXI AND HOPEFULLY FLIGHT 🙂
After the first fast taxi yesterday, we decided that the mixture control valve needs to be adjusted. It doesn’t do anything and engine is running rich all the time.
So yes took it home yesterday.
Just finished with it. Took it apart, checked the fuel mixture valve needle, and had to unscrew it, extend it by about 4mm. No wonder it didn’t do anything. now in the lean position, it touches the valve seat. Apparently you lean off an engine to stop it, so I assume that means no fuel, so it needs to touch the valve seat.
Luckily the gasket in between the two halves was still intact, so I used it again, with some new gasket cement. I like the smell of that stuff 🙂
Thursday I might install the carburetor back on the engine and run it for an hour or so, and play with the mixture control, so I can lean off the engine and get it running like a ………. Don’t know the word 🙂 (dream maybe)
Evan came around today to check out the engine and possibly do some fast taxi’s. He was quite happy with the engine, so had a look at the wind and decided to try a few taxis !!!!!! EXCITING !!!!!
After a few minutes taxiing along the main runway we got to a shorter one, facing into the light southerly. The video quality is not so good, but it gives you a nice impression of how things went today 🙂
First fast taxi:
Close-up of Evan:
Back at the hangar:
Coming back after first fast taxi:
Nice sound, bad video:
Also have a look at this video, taken with my new camera from under the fuselage. I got the camera for my birthday 5 days ago :-). It shows the first taxi:
Here he is turning into the runway and does the first fast taxi, and back again. Have a look at the main landing gear during this first fast taxi. You can see the plane going up a bit (wheels dropping down).
The first fast taxi goes quite well, during the second one (not on this video) he (Evan) basically gives up, something wrong with the engine. I know that the mixture control is not doing anything, so we suspect that the mixture is rich all the time. So rich that one of the cylinders gets to “wet”. We checked the spark plugs to confirm that.
So I have a bit of homework to do; adjust the mixture control valve, by extending the mixture needle. From what I remember, it has some thread, so just a matter of unscrewing a bit, until it touches the valve seat when in the lean position. We suspect that the engine will run a lot nicer and possibly faster after this has been fixed.
During the first run the engine went up to 1600rpm, which is what the propeller is designed for, so that’s great!
Later during the second taxi I suspect that the prop only went to 1500rpm, which is what I saw last week. So everything is consistent.
Just need to adjust that carburetor and things will be fine !!!!!! (I hope, because you never know whats next with planes, but getting very close now !!!!!!!! 🙂 🙂 🙂
GREAT NEWS (4 years and 3 days since the day we decided to start building the Bleriot…)
Yesterday I suddenly remembered some answers I got from Chad, my propeller man (see Mon 4 Nov 2013 above) in the early stages when I was discussing a propeller for my Bleriot in relation to the propeller speed. Have a read (4 Nov 2013 above here on this page) if you are interested. But this is basically what what he said:
The diameter is critical in antique prop design because diameter is leverage and leverage is the most important aspect of good design for high drag antiques. If the prop rpm is lower it means that leverage is greater, an ideal situation for high drag airframes.
And an earlier comment from him:
Gert, People that are not familiar with antique airplanes often think horsepower ratings matter. It doesn’t. Cubic inch displacement and prop diameter matter and these are unrelated to horsepower.
So yesterday I told him about my suspicions of the carburetor and my findings with the propeller speed of about 1500 rpm.
Chad came back to me this morning;
He thinks the 1500rpm is a bit low, but only marginal. He designed it to go about 1575 to 1675rpm. Also he doubts that I am having primer valve leaks, as that would effect the engine speed. Also and I knew this, when flying, it will speed up a little bit more.
He really thinks that the prop is still developing the necessary torque to fly well.
Now I didn’t tell him this, but the first time I saw the tacho speed, the engine went up to about 1600rpm, which is exactly what he designed it for !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 🙂 🙂 🙂
Finally after a 5 week break because all sort of mainly weather related things, a lesson again.
Went early to avoid the easterlies that we have here especially in summer. Lots of circuit work again today. My biggest problem (well not always, and I am getting better) is “ballooning”.
This happens when you are landing. Just before you “crash” into the ground, you round out, to make you fly horizontal. But if you pull the stick a bit to much, you balloon (go up again). The whole idea is to stay horizontal, just above the ground, with the engine idle, so that the plane stalls, and lands.
Oh well more practice to get that right 🙂
Also lots of radio calls, and observing other planes, making sure you know what they do….
Just a rundown of what happens after take off:
Flap position first notch.
Gently pull stick when above 45mph; take off.
Flap position back to Zero at 300ft above ground level (AGL).
When reaching 500ft AGL turn into cross wind leg.
When reaching circuit height, 1000ft AGL, drop nose, reduce power down to 5000rpm, and stay at 1000ft AGL.
Turn into down wind leg.
When in downwind leg, radio call: “Rangiora traffic, Juliet Oscar Romeo, downwind, left hand, zero seven, touch and go, (nr 2,3,4,etc), Rangiora”.
Perform all safety checks as preparation for the landing; Brakes off, Landing Gear in tact, Choke off, Fuel on, Fuel quantity,Flaps at zero, Door hatches closed, Safety harness on, and finally on lookout.
When flying past threshold of runway (start of runway) drop power to 4000rpm, starting the decent, first flap position.
When threshold is 45 deg behind you, turn into the base leg.
I should have descended to 800ft AGL.
Second flap position.
Make absolutely sure no one else is flying into the final lag without going through the circuit.
When time to turn into the final leg, you should be at 500ft AGL.
Turn into final leg, third flap position.
Make radio call: ” Rangiora traffic, Juliet Oscar Romeo, on final, zero seven, touch and go, Rangiora”.
After making the call “on final” no one else is allowed to land until I have.
While descending, control power to make a nice descend path while keeping speed at 55 mph, reaching the runway at the second marking boards.
Ideally engine is at idle power for the last part of the descend.
When just a few feet AGL, pull the stick (round out) to reach a horizontal flight. Don’t pull to hard, as that will make you balloon (go up again).
Gently pull the stick more and more, while flying horizontal.
The nose will go up, and the plane will stall and land on its main landing gear.
Pulling the stick more and more until the noise wheel comes down.
Flaps back to first flap position.
Full power again.
Gently pull stick when above 45mph; take off.
Flap position back to Zero.
—- Wow that’s lots !! —-
ALSO while flying level, in the down wind leg, make sure I am at 1000ft AGL all the time. That is were other pilots expect me to be !!!
Got the first part for this headset. Bought M3 earmuffs.
A class 5+ model with a attenuation of 30db I think it was:
They look massive at the moment, but remember that the helmet will go over my head, and probably cover the red rings of the earmuffs. Plus all of this will be covered in leather, including the earmuffs.
This morning I “installed the back of the seat. Was just a matter of doing up the cable ties I had sticking out at the back. starting to look good, and feels comfy 🙂
Only think left is the little bits of leather sticking out on the front to “tie” it to the side, but that should be done in the next few days.