1/10th Hawker Hurricane

[Piecost]

Mark

I am following this thread with great interest. I would love to find out details of the propeller design i.e. blade angle, twist, chord, etc as well as its mechanical design.

Tim

[Mark.]

Gearing the prop to allow a smaller prop perhaps as Stephen - Prosper,is doing ?

I can't imagine the forces generated in the powertrain of a model this gigantic, but surely they'll be hefty, with a capital h,e,f,t and y. Now, that's not to say that Medieval Europeans said - Oh, like we can't like build these like, yeah, windmills, because we've only got these plastic gearwheels from China . . . in other words there must be a 'gearing solution' for a 1/10 scale Hurricane to be had - but a daunting project, maybe . . . Also to consider is that with gearing where the prop turns faster than the motor, the rubber motor will be bigger (thicker) than for a direct-drive setup - so even more heft required . . .

Picture: suggestion for suitable winder for your model.

Stephen.

I am 100% confident that a geared setup would be doable, but I'm not sure I can see its worth, when I know that the model will fly with the 'standard' rubber motor/prop combo. I would also be limited on space in the nose due to the location of the battery box for the gyro. Yes, I could move it to another location, but even at 1/10 scale, there's not a huge amount of area in the nose itself. Then to add in more weight with it requiring a beefier motor, I feel it would be adding in complication for the sake of it.

Don't get me wrong, I can see the benefit of a geared setup in a rubber model, I just don't see the benefit in this particular application. 

[Mark.]

Mark

I am following this thread with great interest. I would love to find out details of the propeller design i.e. blade angle, twist, chord, etc as well as its mechanical design.

Tim

Thanks for following along! Although I'm not sure how much information I can give you on the propeller blade design, due to tapping into Ivan's many years of flying duration model airplanes - with a lot of success!

The details I can give you though are as follows:

Blade length 9.5"
Blade width at widest point 42mm
Blade carved out of 3/8" medium c grain balsa

As far as blade angle goes, that will be something I can measure when we have carried out the initial setup and trimming flights. Again, I will be tapping into Ivan's knowledge base for this.

I have actually made a start on the carving of the blades today, and have one complete blade.

I'll have to resize some images so I can upload them on to here so you can see the prop hub assembly.

[Piecost]

Thanks Mark, an information is appreciated. My winter project is restoring a mates Ta152H from the FSMWW2 book doubled up to 10:1 scale also. I was considering making a Maxfliart bucket prop, but making an Ivan type prop would be great!

[Mark.]

So hopefully, there should be some images attached showing the propeller blade I've carved today, the process from block, to shaped to finished, a test fit of the blade on the model to see what it looks like, and the prop hub.

[Mark.]

Ok, so here's some more images that show the prop hub and the additions for the adjustable propeller pitch, and also you can just about make out the tubes that support the inserts with the strimmer wire in.

The other 2 images show the finished propeller blade and how much twist you get from a 3/8" sheet of balsa over a 9.5" length. All that's left to do is install the brass tube for the strimmer wire to be secured into.

[Piecost]

Mark, thanks for the photos and statistics. I will study them in detail when it comes to making my own propeller. The nearly vertical photo of the blade is appreciated as it will enable me to reverse engineer the planform. It looks much more slender than the 2 blader I had sketched out for my friends model.

Am I correct in understanding that the strimmer cable is perminantly glued into each blade?

Just a comment; since I am not able to judge if it is right or wrong; but I am supprised how little twist there is along each blade.

I love the idea of adjustable pitch and the elegant solution you have used.

If I may; I have some more questions;
Is there a target finished airframe mass?
Do you have an initial rubber motor mass, number of strands and width in mind?
I look foward to seeing the nose block and to find out if you employ an engineered method of thrustline adjustment or will rely on shims.

I have the Aeromodeller magazines in which Ivan described his scale models. Your build is useful to understand how his methods are applied.


Tim

[Mark.]

Mark, thanks for the photos and statistics. I will study them in detail when it comes to making my own propeller. The nearly vertical photo of the blade is appreciated as it will enable me to reverse engineer the planform. It looks much more slender than the 2 blader I had sketched out for my friends model.

Am I correct in understanding that the strimmer cable is perminantly glued into each blade?

Just a comment; since I am not able to judge if it is right or wrong; but I am supprised how little twist there is along each blade.

I love the idea of adjustable pitch and the elegant solution you have used.

If I may; I have some more questions;
Is there a target finished airframe mass?
Do you have an initial rubber motor mass, number of strands and width in mind?
I look foward to seeing the nose block and to find out if you employ an engineered method of thrustline adjustment or will rely on shims.

I have the Aeromodeller magazines in which Ivan described his scale models. Your build is useful to understand how his methods are applied.


Tim

No problem at all Tim.

Yeah so the strimmer wire glued into the brass tubes on both sides - so into the prop hub and the blade. You set the pitch before the glue has set, so a slow drying CA is the weapon of choice in this instance.

Yeah not much twist at all, but from memory, the blade is positioned at around 43 degrees at the spinner/prop hub on my Mosquito. It's obviously less as the twist in the blade changes towards the tip.

Thanks. The adjustable pitch solution is just very simple, but also effective in its function. It will also make any repairs/replacement to the blades easier too.

As far as weight goes, I genuinely have no idea. When I weighed it recently and it was over 200g, I was disappointed. But you then have a word with yourself and remind yourself that it's a big model. There's a decent amount of wood in the build, but also the electronics too.

Motor strands/weight will also be Ivan's department. He will handle the model and make a suggestion for initial trimming flights. Dependant on how the Hurricane responds to the motor strands, will then dictate if it's changed.

When I've been out with Ivan, thrust line adjustments on these sorts of models are minimal. Any adjustments will be made with shims though. I have toyed with the idea of making a nose ring with the ability to make easy thrust line adjustments, using grub screws, but I'm not decided yet.