rcjunkee

My Feedback: (1)

I flew the Minare for the first time today.
I was shocked how responsive the controls were given the minimal throws.

Once again I know nothing about classic pattern and am hoping the group can answer a few questions :

1) HOW FAST IS THIS SUPPOSED TO GO - The plane seemed to haul along very fast and I am curious if it is exceeding its intended speed. I have a piped webra 50 turning an apc 10x7 at 15,500 rpm. Please comment on how fast / prop choices for classic 40 sized pattern planes.

2) TO PUMP OR NOT TO PUMP - I put an oval tank into the fuselage because it seemed to fit. Obviously there is a great difference between how it runs with a full vs empty tank especially when climbing vertically. By the end of the tank it went lean on me while climbing even though it was on the rich side taking off. Not ideal. Do people typically pump engines in these planes

3) WOULD LIKE TO MEET / FLY WITH SOME EXPERIENCED VINTAGE PATTERN GUYS - I'm in Sacramento and would be interested in attending any events within driving distance of my city so that I could meet and fly with some experienced guys / get some tips in person. In person is always better.

that's about it....thanks for your time everyone.
Please let me know if you need more info to answer my questions.

Regards

Paul Wells

doxilia

My Feedback: (3)

That sounds about right. Those Webra 50's are some ferocious and very light engines!

Do you have a pipe on it or is it giving you that muffled? Do you know what carb you have on the engine (TNI, TNII or Dynamix)? What's the AUW of the model dry? Wet?

Check the height of the fuel tank compared to the carburetor intake. You could probably stand to raise the tank slightly and provided it is up near the engine, you shouldn't need to pump it.

David

rcjunkee

My Feedback: (1)

David, it has a MACs quiet pipe. Not sure if the length is right. will take some playing with no doubt.

The carb is the TN II

I haven't weighed it yet.

Next time I fly it I'll post a vid for folks to watch and comment on.

Really hoping someone replies with an event in California.

TonyF

My Feedback: (92)

There's a pattern contest in Oakdale in two weeks that is also running Classic pattern events. Here's a link to the flyer,

http://www.patternflying.com/NewsDetailPage.aspx?ID=48

They're not running the Pre-Novice and Novice classes, but there will be a lot of guys there, myself included, who can give you a hand.

BTW, if the tank is back on the CG you'll have great difficulty getting it to run right. Get the tank as close to the firewall as possible and as close the centerline of the carb as possible.

rcjunkee

My Feedback: (1)

thanks tony...I'll be at the event and will look for you once there.
Very anxious to get some more information on this great plane and the proper way to set it up and fly it.

by the way the tank is right up against the firewall and is centered.
It is however an oval tank.

regards

Paul

Taurus Flyer

Well(s) Paul,

do you use muffler pressure?

Simple question, important answer!

I did fly a Webra Speed 61 pumped in pattern but when mounted the tank near the firewall it isn't realy needed.
It also has to do with the shape of the tank, dimensions, length, for example in a sleek nose!
For pattern we need full power the whole sequence and than vertical, nose up and a low fuel level is the key fact of course!
When the tank is to big, (and so, too long!) a solution sometimes can be a smaller tank (and so shorter!), but still enough for the pattern program!!
These days I fly a Webra 40 Black Head propulsed Taurus without a pump.
I prefere a fuel pressure regulator and (only in this case constant) pressure on the fuel tank , above a pump,(your mentioned method) but that's a personal choise.

Edit:
To complete the story, it's all also engine dimension and type related. While suction pressures are comparable and more or less independent of engine displacement the tanks of bigger engines will of course be bigger (and longer too), but still most classic 60 / 61 engines did fly pump less but with muffler (tank) pressure.

The earlier engines, vintage, smaller than 60 displacement, smaller bore carb even without muffler pressure.

The real "suckers",Schnuerle scavenged, a piped Webra Speed (61) for example, do need more fuel and so a bigger (and often, longer) tank and often a pump.
Lower suction pressure (the large bore carburetor) can result in more power, but also exacerbates(?) the suction problem, is another example in which case a pump or regulator is really needed!


Cees (TF)

rcjunkee

My Feedback: (1)

Taurus Flyer - thank you for your valuable input. I am very interested in learning about classic pattern. I did not know for instance that full power is used for the sequence ( although I"m assuming this is not the case for nose down sections / maneuvers).

To answer your question I am using muffler pressure (pressure tap at apex of pipe) on an oval 8 oz tank. the tank is very tall.
I am thinking of switching to a round tank. Perhaps a bladder style?

In any case if I cannot get a consistent run without a pump I would still like to know if a pump give me constant fuel pressure throughout the entire tank and if so do I need a special carb or will the Webra TNii work with a pump?

Taurus Flyer

Paul,

For all vertical paths, nose up! we need full power, see the picture as an example. Even the short moments, and often starting to accelerate in the horizontal flight path.
Also horizontal, for example slow roll, inverted etc.

8 oz tank seems to be normal, important is the distance from the spraybar of the carb to the bottom of the tank in vertical, nose up, flight path? For my Taurus, Webra 40 Black Head the distance is less than 20 cm = 8 inch
Bladder tank will be difficult, I am not experienced with it but because the throttle is so important I think that's the reason these never were popular.
The tank pressure has to be related to the power of the engine, high RPM, much power, higher tank pressure. Idle, low pressure.
For this reason the connection between muffler and tank has to be of low drag so the tank can equalise fast enough with muffler pressure.

Next explanation can be a pump or regulator, but I think you have to try first without, the learn curve! Pumps and regulators can give problems too!

What is the diameter of the throat of the carb, the barrel bore?


Cees

rcjunkee

My Feedback: (1)

Cees, I

I will try without pump first. I do believe I should be able to get good runs with my current set up.
Not sure of diameter of the Webra TNii.

I will measure the distance of spray bar to bottom of tank in vertical position.
If too long I will look for a shorter tank.

Taurus Flyer

Paul,

The diameter of the throat to know if the carb is original of dimensions for your situation.
If the distance is much more than my 20 cm / 8 inch you have to leaf fuel in the tank to observe behaviour of the engine! For example 25 % for 26,6 cm distance. So only observe the shorter flights to make a decision to swap the tank or not.
When the fuel level is low it costs more time the pressurize and depressurize the tank, so think about the connection between pipe and tank too, bore of the connections, mud in the connection etc!

Cees

rcjunkee

My Feedback: (1)

distance from spray bar to the rear of tank (which is bottom in vertical flight) is 10".
Something I need to alleviate e.g. shorter tank?

Taurus Flyer

You can check behaviour by filling the tank with for example 20 % and adjust the neelde valve full power, nose up. Than stop the engine and fill the tank 100 %. Start the engine again and observe the RPM horizontal. When this is much lower than with the level of 20 % you can think about swap the tank, if it's possible!

Important still can be the way the pipe is tuned!!!! Normally the length is some longer than for max rpm is needed!! When your pipe is short or even too short that will have influence too. under load it drops out of the curve, but I am not familiar with your brand. Also experience is too long ago for me!.
Cees

rcjunkee

My Feedback: (1)

Cees,

Now we are getting somewhere. Very good info indeed.

My pipe HAS been cut for maximum RPM. I had been trying to get info on how pattern flyers cut their pipes but could find no info so I went for maximum. Please tell me what how I should cut my pipe e.g. percentage of max RPM / behavior or otherwise technique for cutting.

the pipe is a MACs quiet pipe 8.5 cc and the tuning procedure used is described here (although I stopped AT max rpm rather than going past as described) http://www.macspro.com/tuning.asp

In the meantime I will perform the test you describe.

thanks again

Paul

Taurus Flyer

Paul rcjunkee

To do list:

1. Check connection between pipe and fuel tank, look for obstructions and drag generating facts.

2. Measurement of throat diameter to check originality of the carburator

3. Search for information how to tune a pipe for pattern flying (already started, new thread)

Ongoing job:

1. In the meantime Paul will perform the test "tank capacity and dimensions" as described.


It's a good action to split up the subject "tuning of a pipe", more easy to find back in the future when looking for information!

Cees Taurus Flyer

rcjunkee

My Feedback: (1)

@Tony - If I go to the Oakdale pattern contest will I have a chance for a few flights outside of the contest?

If not am I eligible to enter and fly...even if I haven't competed before?

thanks

paul

NM2K

My Feedback: (14)

There is no tank placement that will provide you with consistent running from the beginning of the tank until the end of the tank of fuel. A previous writer is correct in that your present fuel tank location probably offers the best performance without using a fuel pump and regulator.

The best way to run your Webra .50 is with crankcase pressure pumped through a one way valve and then regulated by a Cline or Iron Bay fuel pressure regulator valve. Then your engine will run absolutely even throughout the tank of fuel.


Ed Cregger

rcjunkee

My Feedback: (1)

Ed,

I'll look into these products. thanks.

speed-panzer

My Feedback: (1)

This is a fast plane, and the Webra 50 loves to rev, especially on a tuned pipe.
I would expect the plane to go around 100+mph.

What did you fly before? At this speed, small flap deflections work very well....

If you kept some pieces of your cut-off header, you may try to insert back such a piece of approx. 0.4" lenght into the silicone coupler, between header and pipe. Hopefully the silicone coupler length allows. This may drop peak rpm by 100-200, but you will have a less sensitive set-up afterwards, and a little bit more lifetime in your engine. Of course you should re-check needle valve setting.

Our standard approach for tuning the needle valve on a piped pattern plane is something like this:
Fill the tank 50% full of fuel, tune the needle with airplane in horizontal attitude to max rpm, then open some clicks (depends type and make of carburetor - Webra needles need more clicks, std. OS less....) until you notice very little rpm drop. Now lift the plane into vertical and make sure that rpm will not drop. If it drops, you are too lean.
Re-check after filling tank to full amount that rpm at full open throttle in horizontal attitude does not drop too much below the rpm which you found from first setting. If tank size allows, do not take off with 100% fuel on board, but with something around 85%.

This is a rule of thumb which usually results in a good compromise without hassling pumps or regulators.

Dominik

rcjunkee

My Feedback: (1)

Dominik,

I have flown modern F3D planes before so the speed is nothing to me.
Still I was amazed how clean this airframe is especially given its age.
there was a very strong headwind and it penetrated like it was nothing.
Additionally the elevator was so sensitive on landing that it balloned right before touch down and still was able to coast forward without pancaking.

I have a bunch of aluminum tubing I'm going to use to make extensions for the pipe.
I am wondering however if the speed is too much.
I've never seen classic f3a but have watched some video clips and mine seems a bit fast...might not look as graceful as top speed.
Maybe an 11x6 would be nice or even one of those zinger 10.5 x 7 props. don't know.

In any case I'm going to the competition in two weeks to meet folks and get a feel of how these things are supposed to be flown.

thanks for your reply sir.

paul

KLXMASTER14

There is no such thing as "too fast" in classic pattern. See you at Oakdale.

-Robert

speed-panzer

My Feedback: (1)

Hi Paul,

this agility around the axes as you describe also could be resulting from a c.g. quite far aft.
The pattern planes of the Curare era usually are quite docile, forgiving planes, even with back c.g.
But you may just try to move c.g. about 0.5" forward and watch what happens.

Enjoy the pattern meeting! In July we will have a casual metting of pattern plane pilots here in germany, both recent ones but also classical BPA.

Dominik

rcjunkee

My Feedback: (1)

Dominik,

could be...even my f3d planes were very smooth on the controls...no exponential needed.

the plans (from the kitter...not the original) said to put the cg at 4 3/8 but I ended up at around 4 1/2 - 4 5/8" seemed negligible to me.
I already had to put a heavy brass hub and brass nut on the nose...so much for a light engine.
any extra weight in the front and I might as well just install a 60 / 61 sized motor.
I am guilty of putting too much bondo and paint on the tail.

speed-panzer

My Feedback: (1)

Try to put the c.g. little forward. Those BPA´s easily tolerate some extra ounces, even go smoother through large loops and cuban eights then...

NM2K

My Feedback: (14)

The shortcoming of a .40 to .60 size model, such as the Minare, is that it carries along the same size radio gear/retracts as a larger .60 sized model while providing less lift. This particularly makes knife edge and point rolls much more difficult to execute properly. The cure? Folks usually resort to making the model fly faster - not slower.


Ed Cregger

doxilia

My Feedback: (3)

Good point Ed.

A cure for this syndrome is to build the model lighter. This can be achieved through thinner "shell" frame ups and the use of lighter mini and micro servos (e.g., throttle, retract valve) instead of standard servos which are not needed.

At sub 5 lbs all up, a full house 45 size model is relatively light (wing loading wise) compared to an 8 lb 60 size classic. Even at 6 lbs larger 45 size designs such as Autora's, Dash-5's and Citations are quite light given their wing area.

On the upside, these same models fly comparably to their larger 60 size brethren, consume less fuel and have a higher power to weight ratio. To my mind, this makes them excellent pattern trainers and are a tad lighter on the wallet.

At 5 lbs, Paul has done well with a glass/foam painted piped Minare. However, as we know the Curare is the quintessential ballistic design.

David