Turning Clock or anti clock wise

OOOhhhpppss, yes, thanks Daquiri, we have a misunderstanding. I will have to make another blade now. Not a problem, that is part of the fun. I will bend it than 180 degrees opposite the wrong bend blade.

What would actual happen, if the two wrong concave blades are being welded like as per my photo?. I though it would look good, but a good looking prop may give 80% less thrust. What is actual the consequence? Bert

 

You'd essentially have a prop which works in reverse when the boat is moving forward.

 

With other words, drastically or a reduction in forward speed. Thank you Daiquiri. I am already making new blades as per your (own) photo. Bert

 

Daiquri has it right, the red end should be the aft end. The pitch still looks too high at the tip.
Propcalc is not a great a very good program for propeller design, but the method will work if the parameters are in the correct range. In this case, they really are not in the proper range for the program. However, I suspect that the calculations are more accurate than the building method; sorry, no personal offense meant here.

 

Hey, how about simply painting the other face red?

 

I would than have a very red human face. I am first trying to twist it back the otherway again. If it does not work out nicely and have the blade surface damaged, I will make new ones .

Hell, it take a lot of strength out of me, to bend it. A 2 meter pipe with flat bars welded and 1 inch bolts. Still with the "helping hand" still a quite a job Thanks Daiquiri,

By the way, is it better to have our winter holiday in December 2013 in Austria, or are there also affordable places where you live?.

Your lake is beautifull, but I passed it some 50 years ago. Will have changed drastically by now. Bert

 

Yes, the PROPCALC program has some flaws in it at low power. Example Semi displacement/displacement 1 H.P. >> 1600 Revs >>> gear ratio 4: 1 >>> shaft speed 600 revs instead of 400 and there are a couple of other ones.
If you feel that I can do better and you have a better blade layout for me, I will be grateful. I created the blades by looking at various pictures I took from props on boats at the boatyard. If you are happy with the layout, but I need a liitle more twisting, I will still get it to the degrees you have proposed in a previous thread. I just need a little more muzzle strength.
Bert

 

I am definitely not a winter animal. I can give you advice for great summer vacation spots if you ever decide to visit the med, but when it comes to winter vacations - unfortunately I'm the wrong person to ask. This is the period of the year when I'm trying to mostly focus on the work, so that I don't have to think about how cold and dark it is outside. The objective is - hibernate and survive till spring time, like bears do.

The lake Garda has certainly changed in 50 years, but is still beautiful. However, prices have soured up thanks to Russian and German hi-class tourism. You can find affordable places, of course, but it's better to first define what is the definition of "affordable".

Cheers

 

Thank you Daiquiri,

Affordable means for me, I have a ball, without hunderds of hands are being kept open for a tip, able to rent a good car, have a decent place for the family to sleep in and we can visit historic places. We enjoyed last year in the summer the area of Venice and surroundings. Well, I will try Austria.

I have been able to bend the blade back by 180 degrees. Am busy in milling and turning on the leath the center part. Had to grind the blade further to archieve the 62 degrees and 12 degrees hold onto the center part of the prop. (taken from 90 degrees to the center of the propshaft).

Thanks for all the help. I still haven't been able to repair my computer, sorry for the delayed reply. Have a great 2013, have lots of work at good prices and a brilliant health.
Bert

 

Winter vacation.

Dear BertKu:
Nothing to add to the posts related to the propeller construction. I'd only point to you, BerktKu, that is very important not to forget the matter of the changing angle of the blade. The key is to provide the same pitch all along the blade.
While rotating speed is constant, "linear" speed of each section along the blade, depends on its distance to the rotation axis. Hence if no "twist" is provided the pitch would be different at each distance, leading to performance decrease, mechanical stress.

Have you considered Spain as a winter vacation place ?
At the north, historical places and monuments can be found anywhere, ranging from the Altamira Caves (35.000 years) to the middle ages. Lots of castles, monasteries and churches, from the early middle ages (Romanic and Pre-Romanic; around IX century) to Gothic, the Pilgrims path to Santiago, .... lots and lots of things worth to visit.
Weather and landscapes are Alpine, is quite similar to Switzerland, nothern coasts similar to Ireland or England (Rainy and foggy).

At the south, at Granada, the sunny beaches are only two or three hours far, by car, from the ski facilities at Sierra Nevada.
At the same place, the architectural jewels from the Muslim period of Granada (Alhambra, Generalife), are located.

Weather at the south is sunny, and warm at the coast, even at December.

Of course Spanish accomodations have been rated to be the bests in the world, and prices are cheaper than at Austria.

Hahahaha. I look like a Tourist operator. Im not, but as that Alpine region I told above is my homeland, i love it.

You can Google for Ski facilities at "Formigal", "Candanchu", "Astun", "Panticosa", "Baqueira Beret" and a lot more at the north.
For "Sol y Nieve" (Sun and Snow) at the south.

From my point of view, the north is better in regard to historical and cultural routes, but weather can be rough.
At the south, sunny days and good weather are granted.
Comunications through Spain are quite good, from High speed roads to High velocity trains.

Anyway, hope the best for you along this 2013.

Regards

 

Thank you, I was out of town for 4 days and came only back tonight. Yes I will comply with the 62 degrees at the bottom of the blade and 12 degrees at the tip. ( let me rephrase that. I will do everything in my power to bend it to those degrees. I may be out by 1 or 2 degrees. It is hard labor to bend those 3 mm 316 stainless steel blades !!)

Yes we have been a number of times in Barcelona and along the coast. We did a boat trip starting from Barcelona to the islands once. We even drove from Barcelona via Algarve to Lisboa and flew back to RSA from Lisboa in Portugal. Lovely country, enjoyed every bit of it. In the south similar semi desert as we have here in RSA.
Barcelona was the first stop 47 years ago when I decided to start living in RSA, permanently. The airlines, in those days, flew to RSA with 2 stop overs. one stop in Barcelona and one stop in Algoa. We stayed the night in a beautiful part of Barcelona and strolled around seeing the old historic places.

Yes, I remember that I was driving on the double highway , with very little traffic. We thought, woow, how nice, we could see the busy traffic on the coastal road. Until we hit the toll boot. We than realized, it was a toll road and for most Spanish drivers too expensive. (I am now going 20 years back)

You too.

Bert

 

I think the blades are based on a screw thread? an inclined plane ,wrapped around a cylinder the rise of inclined plane equals pitch.

 

Thanks Rick, If I have understood you correctly, the answer is yes.
Bert

 

Hi BertKu:
Unfortunatelly, Spain is no more "different".
Most roads are now free, but you'd found them quite busy.
Last twenty years have completly changed this country.

Regards and good luck with your propeller.

 

Hi , Well, I feel Spain is still a very attractive country to fly to. I know what you mean, that because of the Euro, it has become more expensive than years ago. But being part of the Euro has quite a number of other advantages. No more visa's thus more people come to your country and spend their money.

We have here in RSA an unfortunate situation that the "NEW" government wants to convert all nice highway's in toll roads. Although the nice double highway roads do exist already.

I was there 3 years ago, we loved it, but took taxi's and trains.

Thank you.
Bert