"New-Bee" Engineering Student from Rhode Island

[nsheryka]

Hey everyone

My name is Nick and i am a senior studying Mechanical Engineering at the University of Rhode Island. I have been studying the plans, and doing a lot of research into the construction of a Gyrobee for the last 8 months now, and become more and more intersted in the design the more i learn about it. I have decided to attempt to build one for myself as an independant senior project durring the summer as well as the next school year.

I would like to, however, build the machine as much from scratch as possible. I work in the Machine Shop for the ME department, so i have access to all the equipment i will need there. I am also in the process of (almost done!!)creating a digital model of the entire machine in Solid Works (a three dimentional CAD program). I will be sure to post pictures when i am finnished.

I am truly glad i found this forum, i have spent the past few days reading over tons of old postings, absorbing as much konwlage on the subject as i can. One thing that i will definatly need to finnish my project is support and an exchange of knowlage from this community. There are a few things that i things that i simply cannot seem to figure out on my own, perhaps some of the members could point me in the correct direction?




1. In regards to pre-rotators, who makes these? where does everyone get them from? are they compatable with all rotor heads??

2. I plan on using the Watson tail group, unless someone can give me a good reason not too.. is this what most people use? any modifications, or right from the Gyrobee Documentation?

3. What do most people use for Cyclic Control, i cant seem to find any plans or technical drawings for one anywhere on the internet. Can someone point me in the right direction?

4. I found some plans for the Rotordyne head online (have modeled this in Solid Works), i cant seem to find a seller anywhere, however i would like to machine my own if possible. can a pre rotator be used with this system? (Wunderlich?)


I have actually just recieved the very first part to my Gyrobee, the ball bearing assembly for this rotor head. Its small, but it is a start. (pic seen attached)

Thanks everyone,

-nick

 

[gyroman]

New Bee

New Bee

Nick,

Congrats on making a wise choice. If you have access to a machine shop and feel confident in making the parts from scratch then by all means have a go. StarBee gyros has most everything you need for the Gyrobee whether you are making from scratch or want to purchase predrilled and cut parts. I would recommend not making your rotorhead unless you are pretty skilled at machining. StarBee also sells a nice rotorhead for the gyrobee. There are several manufacturers that sell heads: dominator, sportcopter, and aircommand just to name a few.

Dick Wunderlich sells the prerotator that most use. It is adaptable to most rotorheads.

Starbee sells a good cyclic also.

StarBee Gyros

I have several modifications (including a cyclic) that some users have done listed on my website (see end of this thread for link).

Good Luck and welcome to "Bee World"....

 

[gyropilot]

GyroBee Family

GyroBee Family

Nick,

Welcome to the GyroBee family.

Regarding the prerotator:

Most people are probably using the flex-shaft prerotator manufactured by Dick Wunderlich. He sells components compatible with most popular rotor heads... especially if they use standard Bensen dimensions. The only problem I had when installing one of these on my particular Bee was with routing the flex shaft due to the mounting location of the bracket that attaches to the gearbox on the engine. I had to make some minor modifications that shouldn't be a problem for you with access to machine tools.

Regarding the Watson tail:

Overall it's a good tail to build, but there are a couple of things I would highly recommend you consider changing.

First, the little hinges Doc Watson built out of aluminum angle are absolutely terrible! He used only 2 of them, so if one failed... uh oh! You need 3 hinges for some redundancy (safety). I also don't like the way he attached the hinges to the tail facings... inaccessible AN bolt heads supposedly held captive from turning inside the tail.

Instead, make your hinges out of AN eye bolts with AN clevis pins, screwed into anchor nuts (permanently fastened inside the tail). When you get to the point of actually building the tail, e-mail me and I'll provide you all the part numbers to use, etc.

Also, it couldn't hurt to make the rudder and vertical stab a little larger... not so wedge shaped like the original. While rudder control authority is adequate when built to the original plans, a little more would be better in some circumstances.

Doug Riley had some good Watson tail tips he shared back in 1999:

A few thoughts. The composite supplies (peel ply, glass, microspheres, feather fill, epoxy) are available from Wicks Aircraft (1-800-WICK) and other homebuilt aircraft suppliers. While ordering from them, also ask for Rutan’s book on foam-and-glass construction. It’s inexpensive and helpful.

You might want to include a counterweight in the balancing tab on the rudder (the part of the rudder that’s ahead of the hinge line). Bensen used to specify 20 oz. of lead to prevent flutter. Doc was unclear as to whether he added weights AFTER testing or before, but he did add them. A 1" dia. steel bolt weighs about 2.7 oz. per inch, so one solution might be to bore a hole in the foam and epoxy a 6" or so steel bolt in it before glassing. Rebar would work, too.

There's a seam in the rudder because it's bigger than stock foam boards. The seam is glued only in the center, so the glue joint doesn't interfere with hot-wiring. After you sand the seam area to your satisfaction, work some pure epoxy into the seam to wet it, then follow with dry micro to bring it up to the surrounding level and proceed with glassing.

You can do some finish contouring to smooth out any ripples left from hot wiring. Use medium-to-coarse sandpaper on a large block and very light pressure. Watch out for hard spots created by the hot wire process; it melts the foam back down to liquid styrene, which then hardens into solid plastic that's denser than the surrounding foam. It's possible to sand too hard against these spots and cause depressions in the neighboring foam. You can fill low spots with dry micro or special composite fillers; sharp dents can be filled with little slices of foam glued down and then sanded.

The plans call for half round wooden strips for the leading edges of the horizontals. The cores are cut so you can omit this step if you want; just gently finish sand the leading edge so it's a nice round surface with a radius of at least 3/8" and glass over. Avoid sharp leading edges; they cause early, abrupt stalls. You'll discover that the horizontals have to have triangular cutouts in the aft inboard sections to allow the rudder to move. The cutout angle should be about 40 deg.

The trim tab goes on the right side of the rudder, and is bent to the right. This deflects the rudder to the left for yaw compensation. Set up the rudder cable lengths so that the rudder is deflected about 10 deg. to the left when the pedals are in neutral position.

The fore aft gap between rudder and vertical fin will have to be about 2" to accommodate the hinges. Important: The rudder horn pattern in Doc’s plans is WRONG; it puts the cable attachment points aft of the hinge line, which causes the rudder to stay flopped to one side. The horns should be made from 2x2 angle stock with a radius in the corner (don't cut out of sharp cornered extruded tubing), and must include an arm that extends forward far enough so the cable attachment pivots line up with the hinge line. For clearance for these horns, you may have to put the inboard lift strut U brackets on the lower bolt of the tailwheel plate, instead of the upper one, so be sure to cut the strut tubes long enough.


I don't care for the cable leads that Doc shows in the plans. As with the rudder horns, they are made out of sharp-cornered angle that cracks easily. At least make them out of angle that has a radius in the inside corner. I would rather see cable leads that allow you to take the leads off the cables, but, as shown on the plans, they’re locked onto the cables once the cable eyes have been clinched. I would also prefer to see either solid rivets or AN hardware used to hold the assembly together.

Don't forget the little horizontal tubular "spars" that attach the horizontals to the fin. The horizontals should have zero to -2 deg. incidence, leading edge down, with reference to the tail tube. Don't give them a leading-edge-up incidence; this will push the gyro’s nose down with throttle or airspeed increases, which is the opposite of a stable response

The cores are cut to allow you to make the cast in place micro epoxy trailing edges described in the plans. This is the fussiest part of the whole operation, though it is the way Rutan did it. If you have access to woodworking machinery, you might be able to make some properly tapered strips of light wood for the trailing edges; the idea is to get some type of internal form that will support the glass until the epoxy hardens. After that, the glass does the work.

For the cyclic:

I built a pump handle cyclic from scratch. Details and drawings are available here on Toby Harvey's The Lone Star Gyro Web Site web site. Click on "Important Tips."

Best regards,

John L.