Assembling the Bleriot / Prop talk

Today, Rutger and I spend about 4 hrs getting the Bleriot ready for the show. All went well !

Luckily we have this massive hangar to do it in. Very wet outside !!! But It looks like the weather is going to be on our side by the time the show starts !!!  🙂

Also, I am getting the feeling that I might have to start looking for a different propeller to get more performance, but will see later. Hopefully we find another thing we can tweak a bit, to squeeze a bit more power out of the Velie 🙂

So yes today I have been talking with a lot of people about my propeller. And the consensus is that I might need a bigger pitch, basically grabbing more air, as the engine itself is powerful enough to pull that through the air.

Would love to just try a prop, any prop, that fits my hub, and see what the difference is. But that hub is the big problem. This hub, mounted on the crank shaft, holding the prop is an old American style one. I would be lucky if I find one.

The bolt pattern is 4 5/8″ (117.475mm) diameter, 6 bolts. That gives you 2 5/16″ (58.7375mm) spacing between bolts!

Just in case someone is reading this: If you have one, let me know. Oh and yes it is a clockwise (from the cockpit) rotating prop !

I did get the name of a guy here in NZ who has been making lots of old style props for famous people, with tons of knowledge, so might start talking with him. He is Jeff Fox, lives on the North Island, around Auckland I think….

First flight ??

Sun 13 Dec 2015:

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 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 🙂 🙂 🙂

So I guess we need to try and fly this machine 🙂

I will tell my test pilot.

1500 rpm

Yes ran up the engine today. Was very windy today so decided to face it out of the wind, with the chocks and 2 pegs into the ground holding down the fuselage.
Getting good at starting this engine, always goes, after a few tries so that’s good 🙂

Now back to the Tacho:

The tacho works now so very happy about it, still want to check it against a external speed sensor, something optical, but yes pleased. The not so good thing is that it possibly doesn’t go as fast as was hoping. It was doing 1500 rpm which according to the manual of the engine equates to about 45 hp. Maximum speed is suppose to be 2000 rpm. I am sure, and always thought that the engine is limited by something. It doesn’t produce any more power from 40% throttle too 100%. Maybe its the carburetor… So soon I will need to start getting some experts in I think, to see what they think.

I also know that, when on the ground, the prop won’t go at the full speed, it will go faster when flying, but I somehow don’t think that’s 1/4 extra….. To be continued.

But happy with the tacho working 🙂

A few hours later:
Still thinking about that carburetor….
The engine runs OK at low rev’s, but at higher rev’s is limited by something. Also the mixture control is not behaving, basically closed mixture, it should slow the engine down, or at least do something, so that’s wrong.

But I have had problems with the priming valve in the past. What if it’s not leaking anymore at low rev’s, but at higher rev’s were the engine is trying to suck more air, its possible that some fuel is starting to come through this priming valve. When I open the priming valve just a little bit while its running, the engine dies straight away, so just a little bit of extra fuel will surly stop it from going to max rev’s. I know that my carburetor is an earlier model and that later models had the priming valve modified because of these or similar issues……

THAT’S my thought at the moment…..

Maybe I should go to a new simple carb that doesn’t have these issues.

Connected hall sensor

Sun 29 Nov 2015:
Spend 3 hours today connecting up the tacho. Time goes so fast when you are having fun…
The plan was to just connect it and run the engine, plus also add the leather covered back on to the seat.

But didn’t go that fast. Soldering the cable to the 3 individual cables going to the tacho gauge had to be done in open air and took ages, but I got there. Oh yes, there is no power in the hangar, so had to push the plane to another one that had power…
Then I had to take one wing of to get access to the gauge.
Luckily every time I needed help, someone happened to walk past and wanted to look at the plane, so that was lucky as they helped me removing the wing and putting it back on 🙂

So next time when I am back, will run up the engine and see how it goes. Hopefully that will be this Wednesday night after work !!!

Magnet poles on prop

1123879_origMade a ring of steel sheeting today, got some cutoffs from work, to form the top of the 8 magnet poles.
Cut 8 bits the right length, and pored some epoxy over the magnets before the steel bits went on.
Then I removed the bits of match sticks, finished filling it up with the epoxy. Looking really good now. Ready to start on the sensor !!!





Fabulous !!

Hall sensor

Got the sensor back that Warren made for me. He has his own business and makes current sensors with hall sensors, so the perfect man to make me a sensor to pick up the magnetic poles on the back of the propeller !
Below two pictures of the sensor, apart from the heat resistant sheeting around the cable, nothing else to see really 🙂

After I installed it I checked if it worked by connecting the supply wire’s to my car battery, parked right in front of the prop and used a volt meter to measure the sensor output.
Perfect, per revolution 4 times a 5V pulse, evenly spread over the revolution, as you would expect with the magnets as shown above.
So soon, I hope, connect the wires to the tacho and run the engine ……………..


Drill holes

Yes, it’s possible to drill the hole up to 1/2″. Might do that as some holes don’t line up perfectly with the holes in the propeller hub. Chad said he would use new 7/16″ bolts and some washers in the flange of the hub to fill up the void, but as the holes don’t line up, its better I think to go up one size.


Today only had a little bit of time to work on my project, dropping of my parents at the airport going back home to The Netherlands, and a birthday party of my 2 year old grandson Levi 🙂

Any way, I found that my new beautiful prop is a little thinner as the original. This means that the 6 bolts going through the prop are a little to long.


Getting advice from Chad at the moment if I can drill the holes a little bigger, from 7/16 to 1/2″. The holes in the prop hub flanges are 1/2″, but the original bolts are 7/16″ except for where they go through the hub.