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Old Mar 09, 2012, 08:52 AM
usaf3kteam
rcgeorge's Avatar
Joined Sep 2005
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I knew that you could do it nice work by the Americans as was predicted four years ago keep it up. Thanks to all of the new molded builders you rock.
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Old Mar 09, 2012, 09:13 AM
Aurora Builder
United States, MD, Lusby
Joined Nov 2003
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Quote:
Originally Posted by G_T View Post
If you look closely at the last photo, bottom fuselage, 2:30 from the front bolt hardpoint to intersect the edge of the wing saddle, you'll see one of the defects. Sometimes they are worse than this. A little West fast + 410 lightweight filler + 423 graphite powder and a touch of wet sanding would make the spots go away.

The pictures really aren't very good. They are crops from pictures showing a bunch of stuff other than just the fuses. Clearer pictures would show the issue better.

I guess the only real benefit of pointing out this sort of thing, is to help people appreciate that when they see some manufacturer put out a nearly perfect part, some skill, experience, and thought went into its creation. I think too often we take for granted the toys we have to play with. It isn't as quick or as simple as it sounds to "just" make a plug, pull a mold, and make great parts from it.

I quit watching the $75 DLG thread. Yep, one can make a DLG for $75 IMO. Once one already has purchased and made the required tools, has the materials purchased in quantity, and knows all about how to do the work. All that part, the expensive part, doesn't come for $75.

I used 1.5 to 2 gallons of aerospace grade epoxy (thankfully I got it cheap or that would have been $450 right there) and 50# of washed kiln dried sand as the raw materials when making my mold. Plus a few pounds of powdered aluminum and probably a pound of graphite powder. Probably a few pounds of cabosil. Yep, it is a workout moving that thing around. I don't think I'll ever make one that heavy again! Plus mixing pails, scrap materials for parting plane, plastic covered foam sheet for blocking the mold. Large ball bearings for alignment. It took me more than a month to make the plug. The plug was pulled from a two piece mold I had made previously, but a lot of reshaping and cleanup went into the new plug. It took me two attempts to make a satisfactory mold from the plug and I had to repair the plug between the attempts. If I damage the mold I need to start over. The plug was damaged again in the second attempt. I even made 16 beefy clamps for the thing. $550 for a good quiet compressor (my shop location requires things to stay quiet, unfortunately, otherwise a cheap compressor would work). I haven't built the hot box yet but since I'm using MGS slow for the layup it is required that the part undergo a heat cycle before being pulled from the mold. I can't make a batch and do it afterwards.

6 prototype fuselages so far, before the first part is sold. Perhaps 4 hours each towards the end, but more like 5 at the start. Plus time making fabric patterns. We'll be making several more prototypes before having everything worked out. That's just the learning curve. If I hadn't made a mold and a cople pods before this, and wasn't working with Phil, things would take a lot longer!

Phil has a nice shop, and knows how to use it!

Anyway our toys are really too cheap in many respects.

Sorry I got somewhat OT. I just want to express appreciation for all the manufacturers making nice planes for us, and for all those who are trying to do so. And I'm glad we are not at a stage where we need to purchase everything. We can make great things ourselves if we put the time and effort into it.

Gerald
+1. If Aurora parts are available, at best I'll be re-couping my investment in tooling and materials. Doubt I'll ever get my time back, if you include R&D on wing, CAD time, building the hotbox, dihedral jig, fabric patterns, foam patterns and time involved in each wing. All this time in engineering dollars makes the expensive materials look cheap.
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Old Mar 09, 2012, 02:57 PM
But I am learning
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USA, MD, Cumberland
Joined Apr 2008
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I got a package today photos and thoughts once I have some more time. Right now I am finishing up the last of the Fr3aK tail tooling.

Brian P.
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Old Mar 09, 2012, 08:46 PM
Registered User
Congress, AZ
Joined Sep 2001
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Phil,

I guess a sign of getting old is when someone reminds me, my reaction is "of course, I remember that:

Gary
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Old Mar 09, 2012, 09:06 PM
But I am learning
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USA, MD, Cumberland
Joined Apr 2008
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So I have been talking with Gerald about this fuse for almost 2 years. I have done my best to give him a friendly push, and then Phil joined in too.

Gerald is a perfectionist, and seeing the molds in person, they are a work of art. The parts that have come out of it are of equal quality. I received #4, and by no means is it a bad blem. I have seen some commercial planes that this quality is better than. There are a few little areas that got air trapped against the mold surface, but other than that its perfect.

There is plenty of room for 285's, and a Lipo. The boom is one of the stiffest I have seen. Also the hoop strength of this thing is 2X better than anything I have purchased.

Keep up the great work Gerald (and Phil)

Here are some better quality photos.

Brian P.
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Old Mar 09, 2012, 09:32 PM
Registered User
Germantown, Maryland
Joined Apr 2004
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I mostly stir the epoxy and try to stay out of the way. I've found that things tend to work out best when I don't touch anything. Gerald is a perfectionist. I am not. Nothing that I touch will be perfect for very long. There are stories that won't be told here
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Old Mar 09, 2012, 09:52 PM
G_T
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Joined Apr 2009
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Quote:
Originally Posted by Paul Harvey View Post
Looking good, will you be offering a stab mount to match, standard or full flying?
Have you tested tail load bending of the tail and what were the results? Is the boom oval? Do you have any more pictures and what's the price?

Paul
Hi Paul,

Sorry I failed to answer a couple of your questions. At some point, time permitting, I'll likely offer both the spring-v option and the conventional tail option. But that will be a little down the road once I'm up to speed with just the fuses. It is very easy to make either tail mount system and to make it quite light. It is perhaps a little harder to do it in a production fashion, as one has to make tooling that will actually last for production!

I haven't decided on the price yet. That will depend somewhat on how much time it ends up taking me to make each one, once I shift into a semi-batch mode for real production. But I can tell you that they won't be cheap. They'll be > $100 for sure.

I'll be shipping them in PVC pipe, probably for about $10 shipping. And I'll say up front that if you don't like it, I'll buy it back you just cover the return shipping.

Gerald
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Old Mar 09, 2012, 10:34 PM
Canada
Joined Jun 2009
434 Posts
Hi Gerald

Thanks for taking the time to answer my questions. I look forward to the opportunity to purchase one when they become available. I'll have to keep a sharp lookout in the forsale section.

Paul
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Last edited by Paul Harvey; Mar 09, 2012 at 10:37 PM. Reason: forgoten coment
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Old Mar 09, 2012, 10:41 PM
Team Hong Kong F3K
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Hong Kong
Joined Sep 2010
3,073 Posts
Hey Gerald, that looks great!
Can you elaborate on why you chose to use a circular boom and not take advantage of the geometry of the oval cross-section? Love how well the 285's fit in.

Thomas
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Last edited by ThomasLee; Mar 09, 2012 at 10:55 PM.
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Old Mar 09, 2012, 11:19 PM
G_T
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Joined Apr 2009
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Hi Thomas,

I wanted slightly non-uniform stiffness in the tailboom. With a seam overlap, one is nearly there. Some alterations in layup...

If a boom is made too oval, then as one provides a side load, the boom wants to twist to shift the load in a direction in which it is less stiff. That is either up or down... If there isn't something in the plane's geometry to determine which way it wants to shift, then the result might not be predictable. This might show up as difficulty in timing the elevator preset to achieve a precise launch rotation.

Whether this may really show up I do not know.

But in any event I wanted only a little asymmetry (compared to some fuselages out there) so it was easiest to do it with a round boom. Next time around I may do something different. Who knows?

I've liked how the radio gear install worked on our old Edge fuselages, so really I just wanted a one piece version of the same. I smoothed it out, cleaned it up, and made it a little stiffer and a little stronger in some ways. The install had a battery pack in the nose, followed by the receiver, and then two 285s in line. The receiver needed to be pulled to pull the battery (rarely done). No switch-jack... I just plugged the battery connector directly into the receiver to turn it on. The system worked well for a couple of years. It was originally designed specifically for this equipment. Time to go one piece!

Gerald
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Old Mar 10, 2012, 08:27 AM
Kyle Clayton
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United States, VA, Dinwiddie
Joined Feb 2008
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Excellent work Gerald!
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Old Mar 13, 2012, 10:55 AM
BenRoberto
Joined Aug 2004
227 Posts
I'm assuming you intend to run internal pushrods for your new fuses.

Do you need reinforcement around the pushrod exit for the elevator? Based on the pics of your previous fuselages -- the pod and boom version -- I didn't see any reinforcement around the exit slot

-- Ben
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Old Mar 13, 2012, 01:37 PM
G_T
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Joined Apr 2009
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Hi Ben,

I do not expect any reinforcement to be needed, unless someone butchers the job. With the layup patterns I've been playing with, these things are probably tougher back there without reinforcement of the tailboom than a normal fuse is after reinforcement is added.

Yep, internal pushrods or pull strings (I personally prefer pushrods, but to each his own...).

Gerald
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Old Mar 19, 2012, 08:55 AM
G_T
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Joined Apr 2009
5,722 Posts
Time flies.

I had some minor damage to the mold and it has now been repaired. I've started moving the operation over to my little shop. I still need to make a hot box and a few other tools before I can start up making fuselages again. I'm quite busy for this next four weeks so I'm doubting there will be a great deal of progress in that time. But it is a top priority right after that.

I'm considering remaking my patterns to reverse the seam orientation. That might fix the cosmetic issue by itself. What appears to be happening is when the fabric is tied back before closing the mold, the fabric gets pulled back and a little air can seep down into the edges of the wing saddle. Once there, the air doesn't really have a good way out. I can likely deal with this without remaking the patterns but it may be better to just change. I have some ideas to try first though.

Gerald
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Old Mar 28, 2012, 12:10 PM
G_T
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Joined Apr 2009
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I suppose I could part with prototype fuselage #6 if someone really wants it. It is a cosmetic blemish - a reject. But structurally it is fine. The blems can be filled with a little black splooge and disappear. It would be a fine fuselage then. The blems are in the wing saddle area. I also haven't cleaned up the edges of the hatch cutout or finalized the size of the hatch to perfectly mate to the fuselage. That's the builder's problem on this one, though for production versions I'm planning to do it. The hatch cutout can be cleaned up with a dremel sanding drum (will raise Kevlar fuzz if done dry but it should work fine) and then cleaned up with a quick bit of wet sanding with medium to course sharp sandpaper. The hatch itself would just need a couple minutes wet sanding the edges with a block to reduce the size a little to fit the hatch rim. I don't have wing mounting screws to send with this one (need to order - I'm out, same as with my threaded inserts for new fuselages) but they are 6-32 and should be steel. You can use Al or Ti, but then you should use some anti-seize compound. Threaded inserts are already in the fuselage.

It will be about three weeks before I am back making prototypes the way things are going, so this is the only one I have available at this time. Discounted to $100 plus shipping (assumed $10 in continental US covering shipping and the PVC pipe I use for packaging) and I can ship tomorrow. Please accept my apology for it being a blem. If I get everything worked out to my liking, I'm expecting the eventual price to be somewhere around $175.

The current Katana etc thread got me thinking that perhaps this fuse could be of use to someone. So first come, only one served. Post here though instead of PM, as my PM box fills quite rapidly and is often unavailable. I'll PM back later today with email, etc, and we can work out payment. Actually, I'll ship first and you can mail a check after inspection. I'll take it back if you don't want it, you would just be out the return shipping. And of course feel free to post whatever you want about it. My preference would be for it to go to someone who has at least a little experience building (as in, not their first DLG).

Gerald
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Last edited by G_T; Mar 30, 2012 at 03:45 PM. Reason: spelling
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