1928 Propeller

[paul hughes]

I am building a 1/2 scale DH71 and I am wondering what to do about the Prop. My quandry is the prop on the full size was about 60" diameter and the hub 16" dia. On the model I will be using a commercial 30" wooden prop but the hub is only about 2.5 "dia.
Using a commercial type spinner would not look right and I don't think I can buy a 8"dia spinner with the correct taper.
Would it be acceptable to make a wooden coller to go over the prop to increase the hub dia. or would that produce vibration.
Any ideas greatfully recieved.

I have now added a photo to help explain my problem.

prop.JPG (38.62 KiB) Viewed 6399 times

[Robin Woodhead]

Try this Paul, CAD profile traced from two pictures on the web.

[paul hughes]

Hi Robin, Thanks for the drawing, Have you drawn it or have you found it somewhere?

[Robin Woodhead]

Paul,

Did a Google search for images of a DH71, used the side view as a Jpeg, put into the CAD package and drew the side profile and scaled it to the size which corosponds to your dimension of 8" dia (200 mm dia).

Suggest you turn a Alum backplate and make a firbe glass cone to suit your model.

regards

Robin

[paul hughes]

Thanks Robin, Making a conventional spinner would be a option, but as you can see from the photo, the spinner cone only fixes to the front of the prop and does not stretch to the back plate.

By the way, i have uploaded a photo but it doesn't seem to of appeared????

[Robin Woodhead]

have a look at this video.
http://www.dh71tigermoth.com/

Google dh71 and select imasges

There is no reason why you should not have the backplate in front of the prop and retained from the front cone onto the prop shaft if that helps.

R

[Robin Woodhead]

Here is a rough drawing of the spinner with the prop blank shown

Robin