Bleriot XI

[J D 8]

Posted by J D 8 on 16/10/2017 13:02:12:

My Bleriot flys much slower than anything else I have,it climbs on full power, at cruse it flys level and at lower setting it decends.As noted before with no power decent is steep but not that fast,just so much drag.

Monsieur,s Bleriot and Morane gave us what today is the standard piston plane set up, engine at the front,wing and pilot in the middle,stabilizer at the rear. However their aircraft were very much experimental in the early days of aviation and their designs very much a compromise to get airborne with the low power heavy engines available at the time. Wings tend to be stubby and broad, nose rather short,long fuselage with lifting tail and a more rearward c of g. These features do tend to lead to a flying machine that has one comfortable flying speed,any more it climbs and less it wants to decend.

Follow Jon's suggestions above and I think you will have a nice flyer. Good luck John.

[Birgir]

Hi

I ‘m still practicing flying and trimming my Bleriot. Now when new season is coming I’m re-reading the suggestions made on this thread preparing for the first flight this summer. Before last year’s season was over I managed to trim the elevator, and CoG for a levelled flight at a little less than full throttle.

The CoG is about 14 cm from the LE edge which is about 4.5 cm behind the spot suggested by Boddo. I now have 425 gr. of lead up front. Bearing this in mind I would think that the problem would be a tail-heavy model rather than nose heavy. BUT the trim needed for the elevator is a down trim of about 12 – 15 deg. (Remember the split stabilizer has a big elevator area)

I’m not sure what I can read into this. Is the stabilizer creating lift which needs to be corrected by down-trim elevator?

This trim must be creating unwanted drag. I wonder if it would be wise to alter the incidence of the stab a little by putting a 1 or 2 mm shims of plywood between the fuselage and the LE of the stab and reducing the down trim of the elevator.

All comments and suggestions are appreciated.

B.

[Don Fry]

Birgir, if the CG is too far back, it will exhibit a sensitive and perhaps uncontrollable elevator response. I once destroyed such an aircraft. Once experienced, not forgotten.

Now you have lost nose lead from it in the course of your experiments. Have you experienced that it

1. Got better?

2 Got twitchy in elevator response?

If 1, continue to remove lead. If 2, enough removed.

But, perhaps check, that your plan is accurate for tailplane incidence.

But don't be surprised that stated CG we'll forward of the fully trimmed position.

Edited By Don Fry on 19/04/2018 19:48:42

[Birgir]

Hi

When reading my explanations again I now see that I might have switched the phrases “up” and “down” . What I ment to say is that the elevator trim needs to push the tail down, but that is an up trim, isn’t it?

So that is what is baffling me. The tail needs to be pushed down even though the CoG is 4.5 cm behind the marking on the plan.

But to answer Donald’s questions:

Yes, it got better and better when loosing the lead and at 425 gr. I thought it was quite manageable although it was a bit twitchy. After reducing the throw of the elevator that also got better and I decided to practice with that setup. I also checked the incidence yesterday and it is according to plan.

B.

[Don Fry]

Birgir, designers usually give a safe forward CG to launch for a maiden flight. It gets you down in one piece, and gives you time to trim it.

But that CG is not the optimal CG for a trimmed model.

Have you got exponential on the elevator, if not, if your transmitter supports it, it would help in smoothing out elevator response. Another thought, is the control throw to the elevator optimised mechanically to give the desired throw. It should be. Reducing throw using the transmitters programming is a poor substitute for mechanical trimming, and can result in course control response.

But regarding the lead, I suggest you have not got to the end of the removal process yet.

[Birgir]

Hi everyone

At last I managed to do two proper flights with my Bleriot XI.

This morning the conditions in Eyrarbakki where perfect, calm weather and the field at its absolutely best.

I took my Bleriot to the field and manged two proper take-offs, trimmed the plane for level flight with about 60 – 75% throttle and managed a very acceptable landing,- twice!

Here is a very short video of the accomplishment 😊

B.

[AVC]

Nice place, nice video and nice model!!

Is it the perspective, or does the model looks a bit tail heavy once in the air?

[Birgir]

Thanks AVC

Yes, it looks a bit tail heavy, but the reason probably is that I'm holding the tail down trying to gain some hight.

The engine is a little SC 30 FS so the power is marginal.

B.

[AVC]

Nice plane anyway, right back to the origins of the aviation! And it's very nicely finished, good job!

[J D 8]

Good job, flight pattern / turns look much the same as mine.It is just the Bleriot way a bit wallow now and then while dragging the tail around the turn. Well done.

[Don Fry]

Birgir, well done. Have you thought that if you saved up, you could put a 52 in that.

[Birgir]

Thanks Donald

Yes, it has crossed my mind to put in a bigger engine but the front of the fuselage is more or less designed around the 30 so it would call for more changes than I would want to do.

I’ve also got hooked on the challenge of flying with the marginal power, it is more demanding 😊

Yesterday I put in a new plug and now it is running almost 9000 rev. spinning a 10x5 and that helped a lot on take-off.

Maybe it is time for me to carry on with the next project, the Bleriot has been THE project for almost three years now.

Thanks for all the help along the way.

B.

[David Germany]

Hi Birgir,

I realise it's some time now since your Bleriot was on topic but I'm after a bit of info subsequent to crashing mine at the weekend. My error, let the airspeed drop too far on the landing approach in zero wind, dropped onto the runway from about 5 feet.

It's not as bad as it looks, the rear 'birdcage' has shattered and the front undercarriage support structure has broken away. All flying surfaces are undamaged.

As I no longer fly at an electric only site I'm thinking of rebuilding as IC powered. What was your final ballast weight with the SC30FS ? I have a Saito 45 Special which is 470g, and an RCV58CD which is 540g. My preference would be the RCV as it is compact and sounds a bit more scale than the Saito. It also runs great inverted. If these weights are less than your total up-front weight I should be OK.

Hope your Bleriot is still surviving,

David

[J D 8]

HI David, Sorry to see your Bleriot in such a state. Not sure I can advise on an IC set up for your model. My Bleriot is somewhat larger with a span of about eighty inches and has ample power from a 1970's Webra 61.

One thing to note with the Bleriot is it is a light and draggy airframe and looses speed very quickly when power is reduce. Mine becomes more of a parachute than an aeroplane if you chop the power and the nose needs to be pushed down promptly. I therefor fly the aircraft with some power on all the way to the ground.

The early basic design of the Bleriot results in a somewhat one speed machine, more power it climbs, middle for level cruse, low power and it descends I tend to fly mine mostly using throttle and rudder with only minor elevator input.

[J D 8]

View of engine set up in mine, Webra 61 with a modern carb and homemade exhaust to fit in the cowl. Cheers, John.

[Birgir]

Hi David

I’m sorry for your not so soft landing, but bear in mind that Luis also had a tough landing in England on the 25th of July 1909 and also broke his landing gear.

By the way, I also learned the hard way that the Bleriot is no glider, so just look at this as an opportunity to redesign the engine room.

My Bleriot has been hanging from the sealing of my garage since last year so it is still in a pretty good condition.

To answer your question, my Bleriot has 425 gr of lead up front so I think that it would be good to put in a larger engine and use some of that weight to create power. My SC30FS needs full power almost all the time to cope with the heavy model.

Usually when you come home with a broken model it looks a bit better after some inspection and rebuild planning, hope that this is also the case this time.

Please post some pictures of the rebuilding procedure.

Good luck,
Birgir

[Birgir]

 

Hello again dear friends

 

It is now seven years since I built the Bleriot XI model and time to inspect the landing gear.  So, I cleaned it up and put in new rubber bands.  Hopefully she will get airborne again in the new year.

 

Best wishes,
Birgir

 

 

 

[J D 8]

  Not had a go at flying mine this year, it seemed always windy when I could go flying. 

  Pic below is of Denys Corbett Wilson the first to fly across the Irish sea from Goodwick West Wales to Enniscorthy Wexford Ireland on 22 April 1912. Photo was taken in a field near where I live with Denys looking rather pensive as about to depart. 

Fame for this feat eluded him as the Titanic sank the same week.

  Second pic shows his Bleriot parked up against hedge in said field the night before attracting a lot of local interest. Third photo the close up shows his roller map navigation unit used when flying cross country. Cheers, John.

[Birgir]

Hi everyone.

It’s now almost a year since my last post here, where I talked about my hopes that the Bleriot would be airborne again this season. I’m sorry to say that I used all the limited time of good weather here in Iceland to try to master the flying of my biplane, Sig Hog Bipe, with limited results. 

 

On windy days I however managed to make some more videos looking closer at some aspects of my Bleriot XI model.

 

Here below is a video where I take a closer look at the stabilizer.  You can also go to my YouTube channel and have a look at all my Bleriot videos at the Bleriot playlist.

 

At present I ‘m collecting as many subscribers as I can and will be thankful if you could use this opportunity to subscribe to my YouTube channel.

Thanks,
Birgir.

 

 

[J D 8]

Hi Birgir, Weather has been poor for Bleriot flying this year on the Welsh coast, just lots of wind much of the time. Did though have a very good day with my Bleriot last month, Five very good flights gracefully sailing the sky.  John.