PZL 62 + Baby Bee

Long time since last update, but we are progressing!
I finally covered the wings, and I have to say I was pleased with the result. The bottom side came out pretty much flawless, there are some rather minor wrinkles on the top side, where the trailing edge meets the fuselage. Even the wing tips came out just fine.

Sorry for the poor quality pics, I was forced to shoot photos in poor light.

I weighed the plane today. It's 230g (9oz), not including:
- paint on wings
- pushrods
- canopy

So I hope to fit into 250g, I guess that's a reasonable weight.

Try 1.2 mm carbon fibre rods Dirk. Nice and light, no blow back
on 'push' and just a few Pennies off EBay.

Thanks, I have some of these spare, I think.

I printed out the decorations today:

Out of local patriotism, I decided to use the insignia of the 132'nd Fighter Squadron, which used to be located near where I live during the war.
[historical digression]
Equipped with 10 P.11 fighters + additional 6 from reserves, the squadron shot down 5 He111s, 10 Do17s, 3 Bf109s, 3 Bf110s and damaged one Hs126, itself loosing all but two aircraft.
[/historical digression]

I also attached the elevator using stiched hinges.

dirk gently wrote:...I also attached the elevator using stitched hinges.

Ah, another convert to stitched hinges, good going. I have to thank Ken for getting me started.

Decorated fuselage



I also tested the engine, and turned out that there is no problem with starting it with the cylinder hanging upside down

Fully covered and painted:

I tried to maiden it yesterday, I was not particularly succesfull:



At 0:11 you can see the propeller hitting my finger as a result of my carelessness.
At 0:23 the canopy falls off.
Overall, I think it was tail-heavy. I moved the battery way forward and will try again. There is some damage from when it hit the ground, but nothing a bit of epoxy can't fix.

Looking good Dirk.
Advice...?
The first thing I tell my guys is,-
Height is your friend, fly 2 (or3)
Mistakes high.
Take off and get lots of height particularly
On an untried and untrimmed plane before
Attempting even a turn.
Put a couple elastic bands on the canopy
To keep it on and try again.
Looking forward to the next vid.

Those high power magnets do a good job too.

http://www.amazon.com/Applied-Magnets-Earth-Neodymium-Discs/dp/B0012AUU84

You can either do a magnet to a steel tab or a magnet to a magnet. These are surprisingly secure.

Phil

Thanks for all the tips guys.
BTW, looking at the video, don't you think the engine is lacking thrust a bit? I have a 6x4 prop, I guess that should be ok?

Aaah I thought the bee sounded a little
Pedestrian.
I'd say ideally a 5x3.
I know the engines are different but my
Extreme recently has
Turned Bernies yellow 5 3 at around 20.5k
A standard Cox 5x3 at a shade under 20
And amazingly runs a 6x3 at less than 14

Although I haven't tried it at the field cos it's
Been too cold to mess around with props the
Comparative Lack of thrust from the 6x3 is
Astonishing.
That 6x4 isn't doing you any favours.

If you haven't got any of Bernies finest PM
And I'll send you one.
I know it won't look very 'scale' ( you could
Paint it) but it will really wake that bird up.

I'm sure I will get more RPM from a smaller prop, but will I get more thrust?

Yeah
If you imagine trying to pull away from a set of traffic lights
In 4th or 5th gear that's what the Bee is doing at the Mo.
One of the guys put a fantastic utility on here which I refer to
Most days, let me see if I can find it.

There you go Dirk,-

http://personal.osi.hu/fuzesisz/strc_eng/index.htm

It's one of the best (if not the best) things I've ever come across on this Forum but don't
tell anyone else cos they'll all start getting great performance from their engines and where
would we be then?


I input standard prop and flit between 32f and 50f depending on the day, not many 50f days so far
this year,

If you put my Extreme's example of 5x3 @20500, 5x3@19800 and then 6x3 at 13700 and look at
the difference on the 'thrust o meter'.
I should also point out that in the Extreme's current state (which was over compressed as it turns out...)
the 6x3 was soo over geared it wouldn't hold 13,700 for more than a few seconds and kept dropping back into the 12's.
Then imagine your Bee turning the 6x4 at 11/11500 7oz thrust as
opposed to a 5x3 at 17500 at almost 9oz

So on mine we're talking of nearly a 30% loss.
Now I know there are other variables like drag, prop efficiency etc, but bear in mind but the things that
are constant eg the noise ie much higher pitch when faster and most importantly the pull of the
aircraft.

Thanks a lot!,

now, I will have to measure the RPM, I guess that will be pretty easy to do, even without a tachometer. I will just keep in mind, 10k RPM equal 166Hz, and I will employ my musical education

EDIT: the plane is mended together already. Do you think I could just cut down 1cm of the prop on each blade (and, obviously, rebalance it afterwards) before I get a proper airscrew?

Any time Mate.
Unless you're desperate to fly this week I'd
Leave the prop alone, you never know
When a 6 4 might come in handy.
Pm your address and you should get it by the
Weekend.

These 6x4 are readily available here, so no real harm in cutting one down (even if I end up destroying it - yes I am desperate to fly).
Now, the smaller props are only available for electric motors. This is due to the fact that the smallest IC engine you can buy here is 1cc, so no props smaller than 6'' are needed.

6x3 and 6x4 are what I run on my control line models. They pull much more than 5x3 or 5x4 props. You may also want to consider a 7x3, but it will load the engine up and pull your RPM down quite a bit, but will provide an incredible amount of thrust.

This is a case of thrust needed vs speed needed. The smaller diameter steep pitch prop will provide more speed, while a larger flatter prop provides more thrust.

Phil

My money's on Dirk liking the the 5x3 more.

If (big If) the weather sorts itself out for this weekend
I'll do a 'back to back' test of 5x3 and 6x3 I
predict the 6x3 prob won't even ROG.

Based on frequency measurements, the engine only does 10300RPM
I did set it somewhat rich, as it tends to go lean as the fuel runs out, but still...

That seems low but the tach is going to prove it out though. Try a chopped down prop and see what happens.

I am kicking around testing a number of different props on a single motor to see what the results are since I just got my tach.

I probably missed this earlier in the thread, is this an older baby bee that has only one bypass or no boost ports? or a new one that has the smaller intake but the more performance cylinder?

Phil