Building props

[Hans S]

Does anyone know where I can get some software on designing a prop I could build myself?

 

I've heard other people that have built fixed pitch, anyone ever try building a cs prop from scratch?

[Big Steve]

Hans:

 

I want to try my hand also at prop building. I will settle for a 2 blade fixed composite though. I am going to build a copier machine and then beg a used prob off of the boards. I dont think I am savy enough to try and figure one out by airfoil design. STeve

[Hans S]

I was kind of thinking the same thing. Either copy an existing, or find some kind of 3d software where you just put in all the numbers and it pukes you out templates.

 

I have access to a machine shop and was also thinking about trying my hand at building my own cs or at least a manual variable pitch.

[Edge 513]

Newbie- not prenoobie experience.

After I had justfirst started building and went to an accomplished [finished] builders hanger with another builder that was his friend, this happened to mawah.

This flyer didn't know me from Adam but was nice enough to open his hanger and show me his craft. Ted [my friend] had already seen it several times. I was really impressed with his wheelpants. Cookie's[Jay's] plane was very nice. Lots of nice work... but I was fixated in my recent websearching about wheelpants- and like Scrat and his prehistoric acorn...low and behold at the ends of these gear hoops....AHHH, HERE WERE some DANDIES!

Many pleasantries were exchanged, and and finally I began asking Cookie all about the process he had gone through to custom build these pants of his. Time went by in the exchange and while he was a nice guy and all...he finally asked at what stage I was at in my build. I replied.

He frustratingly, constipatingly screwed up a facial expression that would put Red Skelton to shame, with greattttt restraint, said in his Norwegian accent, "Vy are you so concerned about dees NOW...ask me about dees if you finish your aeroplane".

The pregnant pause.

The "if" was not lost on me, as it hung in the air like an unanswered challenge to my new undertaking.

Worrying about the prop now is kinda about like those rascal wheelpants. Talk about it after you've spent 5-10years building something to hang it on.

At least thats what the look was all about in that Cozy flyers eyes that evening in Hollister.

 

I should say that by the end of our get together Jay offered to glass me up a set of wheelpants from his molds, when I finally needed them. Unsaid and unseen though still hangs the "if" over me, like a ghost of all the stalled and unfinished builders with projects they are going to "start working again on that thing next week". Pray for me. I don't wanna stop wanting to finish. Someday I want the scarlett -IF- washed off my cute little EAA baseball cap I like to wear.

Do you?

[macleodm3]

I agree with what you said Edge... and I've done it myself. I can remember worrying about what PSRU to get before I even had my plans.

 

BUT... we all need to look at all the possibilities with building our own plane and at the same time it may take some time to let the whole concept of building our own plane "sink in". It took awhile before I was 100% on building (couple a weeks maybe).

[Hans S]

Edge, I agree with you, but look at it this way. Let's say I run out of foam or epoxy, or any of the other things out there and I'm waiting for it to be shipped. All the other odds and ends are done, playing with a prop would be a good waste of time.

 

Now, on the other hand, a cs or variable is going to take some effort in putting together. A good couple of months if I don't come across plans, a scrapped one, or someone with the know how on how to build one. If this turns into the last thing I'm waiting for, that would be a few months that it sits without its first takeoff.

 

I haven't decided on an engine yet, or a bunch of other things at that. My plans won't get to me until Nov. Having an intimate knowledge of them now will save time later when I'm ready to get to that stage.

 

You can fly without wheelpants, not a prop.

[Edge 513]

Your point is acknowledged..even if it is covered with hair.=] Mine is covered by my before mentioned approved EAA attire.

 

Just in my previous story, my mouse sized point was...It's just not prudent to be planning your wedding night after you just met the lady...'speshally if as a noob, one figuratively looks like Don Knotts or Marty Feldman. You be the judge. I personally am my own worse critic.

 

The girrrls might chime in here.[about the planning thing only plz=]

 

Oh...And if I fly without pants, it may be considered a crime...Jerry has been accused of that with his "pressed ham incident", and it is documented. So personally I will be considering pants as PROPer first flight attire. Ahem.

[Richard Schubert]

Guys that have built their own propellers have used this program with reported good success. Bates engineering prop optimizer

http://www.geocities.com/aeroopt/index.html

[chasingmars]

Now, on the other hand, a cs or variable is going to take some effort in putting together. A good couple of months if I don't come across plans, a scrapped one, or someone with the know how on how to build one.

Designing and building your own homespun constant speed prop? I have to ask whether you consider yourself both a competant engineer (of two or three types) AND a competent machinist? You may wish to look at what's involved in such a beast, the tolerances involved, and how much innovation you're interested in hanging your life on. "Some effort" is an understatement along the lines of... well, I suppose it could be done, but, yeah, engineer and machinist skills needed to a significant degree.

 

As to fixed pitch props, while it takes more work that google, and much more work that just spitting out new questions in threads, I'd suggest that near forgotten breed - the library. A university engineering library if possible. There's a fair bit of (managable) math (if you get vectors, you can understand it easily enough), but a fixed pitch prop isn't rocket science. While there are computer programs to help design props, my own opinion is that if you don't understand what the computer program is doing behind the scenes, and why, at least to a pretty good degree, you probably should leave it alone. But that's just my opinion.

 

As to contingencies - speaking as someone who's run out of epoxy... for best chances of finishing your plane, your action on running out of epoxy should be to obtain more epoxy, rather than design a CS prop. In the meantime, if there is a meantime, carve your next few pieces of foam, read the plans, etc.

[Big Steve]

Edge:

 

You de man: I could not have said it better. I think a lot of the Probies

(I like NCIS) Have a tendency to get all excited about there new Idea of building and airplane. They get excited about motors that dont exist or some slick salesman at Oshkosh promises them will be ready when they finish. I believe in looking ahead it keeps me busy thinking about the whole project. I plan on building my own prop. In 4 years or so I talk about it but dont spend to much time on it because right now I am building my landing gear This in itself takes lots of concentration. I do like to think, and act, a chapt. or 2 ahead of time it keeps me from running out of things to work on. So all you probies or non builders Try to concentrate on BUYING your plans first then try and stay ahead of your build. It only takes 2-3 thousand hours to build one of these puppies. my .02 STeve

[Hans S]

The libraries around here have been no help.

 

When I meant from scratch, I guess I was a little vague. I was talking fixed pitch as my engine choice may be different than stock, hence,I'll want a prop designed for my plane. As far as CS, yes, I have the machinist skills. I can build the parts, I was looking for a design that was already made. Most all work the same way, I was just wondering if one of them engineering types had worked it out and was willing to share. Maybe say, MT selling a plans form of their products:rolleyes: . And I've seen the parts in other cs units, I can machine it a heck of a lot cheaper than ten grand. Tearing one apart to reverse engineer isn't what I had in mind, unless that was all I could find. But building one from a set of already designed plans was.

 

I'd like to build everything I can myself, just for self ego if anything else.

 

And I do want to understand prop design, borrowing one and running it through a duplicator is just that, duplication with no understanding.

 

The running out of epoxy was just an example, my wife would be able to keep me from being idle, honey do lists galore.

 

My plans won't arrive here till the first week of Nov. So untill they arrive, I'm just deciding on what changes and upgrades I want to make before I even buy the first chunk of foam. Dream now, compromise later.

 

Planning 2 chapters ahead? One change at the end can cause changes in every other chapter. I plan on having all mods and upgrades figured in before I even start building. I hate rework, it's a pet peeve.

[dtoften]

http://www.mh-aerotools.de/airfoils/javaprop.htm