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Houston, I have a problem!!!!

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Old 01-03-2013, 02:08 PM
  #26
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Default RE: Houston, I have a problem!!!!


Quote:
ORIGINAL: erik valdez

I belive thats ''Houston''.
I'm shur that's 'believe'. *snicker* There's a joke in there... keep it going!

I'm a 'Cougar'.... go Cooooooogs! Doctorate, U of H '89.
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Old 01-03-2013, 02:26 PM
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Quote:
ORIGINAL: erik valdez

I belive thats "Houston".
erik (no capital e as you write your name),

Of course "I belive thats "Houston" are also typos that should be written "I believe that is "Houston".

I considered the possibility that he is addressing himself to John Huston a film maker.

I also considered that it may have been just a "typo" so I did not react to it.

I often make typos that I sometime correct days later if I notice them.

Zor
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Old 01-03-2013, 02:39 PM
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Default RE: Houston, I have a problem!!!!


Quote:
ORIGINAL: vicman


FWIW, I think there is a ''Master Builder'' in South Carolina looking to do some ''Profeshunal'' work.

OK, I have to admit that made me laugh...
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Old 01-03-2013, 03:12 PM
  #29
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Default RE: Houston, I have a problem!!!!

Quote:
This is like going to school on a PC 

What, like high school? I agree !!
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Old 01-03-2013, 03:54 PM
  #30
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Default RE: Houston, I have a problem!!!!

Hi Gene,

First off; Great looking plane. Quite unusual and different from the normal fare. That's always cool. And as per usual another fine job turned in by you on the build

I took my first foray into floats with a GP 40 Cub which is a very forgiving bird with respect to floats. I learned very quickly that having the step located at the right place was a HUGE factor in how well it would take off, or even if it would ever break water.

Just tossing that out there because I didn't see that anyone else had addressed step location. The Cub likes the step located just behind the CG and the float tips to be just slightly low vs wing chord line....positive wing incidence abour 2 degrees.

Don't forget to recheck balance and CG with the floats on...it will have changed with the floats mounted.

Link to a useful thread below.

Once you get it, you're going to really enjoy flying off water

Best wishes




http://www.rcuniverse.com/forum/m_40.../tm.htm#402539
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Old 01-03-2013, 05:09 PM
  #31
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Default RE: Houston, I have a problem!!!!

Sorry about my spelling. I spent the day in the shop going through the floats and legs. I found my big error and changed the legs on the one side. All went well until I put the plane on the ground and the fuse is in a nose dive position. Looks like I will need to make up a complete new set for the front legs about two inches longer. This is harder then building both planes was. Bending wire is easy but I'm sick of taking the plane apart and assembling it again. I may walk across the street and use my neighbors SPA to float it.
Here is a question: If it floats the way it should and the fuse is level while it's floating do I still have to level it so it's pointed up? I think I already know the answer but like I said, I'm sick of fooling with it.
Fret, you made me look, I went out and checked the CG, still in the same place I had it when I was flying it from land. I do CG just a bit aft but it has gone just a bit forward from where I had it.
I just looked at the photo, it's really pointing down!!! When I was doing it I was thinking I saved myself a trip to the hobby shop. Wrong again. I may never remove the floats once it is set up correctly!!
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Old 01-03-2013, 05:39 PM
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Default RE: Houston, I have a problem!!!!

Glad you got it speeled writh Gene.

I kinda like my little town.
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Old 01-03-2013, 05:43 PM
  #33
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Default RE: Houston, I have a problem!!!!

Gray Beard,

For your information ___

A float plane sitting on the water surface should have a main wingincidence to the water surface of 2 to 3 degrees. Leading edge higher than the trailing edge.

The step of the floats is best located just about at 5% to 7% of the elevators moment arm behind the CG.

Anyone is free to disagree and post their own outlook.

Zor


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Old 01-03-2013, 05:57 PM
  #34
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Default RE: Houston, I have a problem!!!!

Zor, that's correct. The step should be at or just behind the CG. Wing should have a little positive incidence when in the water. 

I know what you mean,GB, but hang in there for us. This is a classic design and deserves the attention to detail. Just don't trip and step on de tail. [8D]
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Old 01-03-2013, 06:29 PM
  #35
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Default RE: Houston, I have a problem!!!!


Quote:
ORIGINAL: GaryHarris

Glad you got it speeled writh Gene.

I kinda like my little town.
Thought it was a country of it's own!!
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Old 01-03-2013, 06:38 PM
  #36
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Default RE: Houston, I have a problem!!!!


Quote:
ORIGINAL: Zor

Gray Beard,

For your information _ _ _

A float plane sitting on the water surface should have a main wing incidence to the water surface of 2 to 3 degrees. Leading edge higher than the trailing edge.

The step of the floats is best located just about at 5% to 7% of the elevators moment arm behind the CG.

Anyone is free to disagree and post their own outlook.

Zor


OK, so even if the plane is in a nose down position like it is when just sitting on land then when on the water the wing should have a couple of positive degrees of incidence? How it sits on land doesn't mater? If I float it as is and the wing is in the up /incidence + then it's OK? As I said I know nothing about float planes. I hope that question makes sense. On water when floating the fuse should be in the up position?
With every question I'm feeling dumber and dumber.[&o] Or, do I have to put a couple of degrees incidence into the wing? It is set at zero as to the plans. Flies great that way. None of that flat bottom wing rise when on the throttle like a trainer.
This could be worse, I could have gone electric like I had first planed.
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Old 01-03-2013, 06:40 PM
  #37
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Default RE: Houston, I have a problem!!!!


Quote:
ORIGINAL: Gray Beard


Quote:
ORIGINAL: GaryHarris

Glad you got it speeled writh Gene.

I kinda like my little town.
Thought it was a country of it's own!!
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Old 01-03-2013, 07:36 PM
  #38
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Default RE: Houston, I have a problem!!!!

If you've got access to any back issues of RC Modeler, Chuck Cunningham did a series of articles in the mid 90's on floats and how to set them up for pretty much any plane. I've only had 1 plane set up on floats, I followed the instructions in the articles and they came out perfect. The first time I took the plane out for a test, I had no intention of flying it at the time, just a taxi test. They worked so well that the plane popped into the air so quick that it scared me and I almost crashed it back into the water.
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Old 01-03-2013, 08:26 PM
  #39
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Default RE: Houston, I have a problem!!!!

Does the plane set on the gear with negative wing incidence when on the ground? I didn't notice that in the other pics. Any trouble rotating for takeoff?
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Old 01-03-2013, 09:09 PM
  #40
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Default RE: Houston, I have a problem!!!!

The wing to the fuse or datum line is set at zero and so is the stab.
There was an article in MAN in the same issue of the build article about float set up in 89. I think it was written by Cunningham, I will look but as I recall it was just about the gear leg set up? It may have only been part one? I will have to locate the magazine, I think it is in the house but I have a couple book racks.
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Old 01-03-2013, 09:26 PM
  #41
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Default RE: Houston, I have a problem!!!!

On land gear. Pretty hard to tell by looking, the gull wing sort of messes the mark one eye ball up a lot. The incidence meter says zero wing incidence. I spend a lot of time setting up the incidences of all my planes. Usually time well spent.
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Old 01-03-2013, 10:58 PM
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Default RE: Houston, I have a problem!!!!

Gene,

The Cub had a flat bottom wing so it was an easy incidence set-up and I did floats for a Hal Davis Sportee40(Forefather of the super sportster40) as well. On the Cub I measured the distance between the bottom of the wing at the front and back to the top of the float and on the SS40 from the middle of the LE and the TE(symetrical wing)to the float. Had them equal at first and i was squirrely on the takeoff and had trouble lifting out of the water...landings tended to skip and balloon...hard to save from the following stall. I put some spacers in the front mount to raise the LE of the wing 1/4" higher than the the TE relative to the float and it started to act sensibly. I experimented with an 1/8 up to 1/2" difference and 1/4" was best for both of those. If you can incorporate the ability to use spacers at the front it will help you to dial it in when you actually get it flying.

No need to redesign or modify any of the angles, incidences or datum of the plane itself...it's all about the AOA of the whole plane when you get on step during the takeoff run. The easiest reference point for the set up is the wing so that's what everyone refers to. If the plane flys well in the air you already have that part of the equation dialed in...now it's just getting the plane comfortably mated to the float set.

It helps to think of it from the viewpoint that on wheels you have a great deal of pitch control to pin it to the runway or yank it into the sky. On floats you have very little usable pitch control...it's all in the setup. If you try to hold it down on the water you will submarine the tips and loose speed...if you try to pull the nose up too much you'll drag the tails and loose speed. Either way you wind up with a motorboat and not an airplane. When you get that wing to float incidence dialed in, the take-off becomes a virtually elevator free proceedure. As you get up to speed and on step the wing is trying to rise/climb ever so slightly and breakfree of the water with no input from you due to the preset AOA or incidence. The water is literally holding the plane down with a suction-like effect, but as you go faster, less and less of the float is in the water and the drag decreases, speed and lift increase until you're up and away.

Doesn't really matter how it sits at rest in the water, though they typically sit between level to noticibly nose high; it's how the wing AOA is at speed when the float planes out.

I'm vicariously re-living my early trials and tribulations with floats through your learning of this new skill set, but at the other end it's been worth it.

We're all cheering for you
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Old 01-04-2013, 08:02 AM
  #43
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Default RE: Houston, I have a problem!!!!

Hello Gray Beard,
Looking at your photo in post 31, I wondered if you would be
able to swap the wires from front to back, to reverse their heights.
That might give the plane a positive angle to the floats.
If they are not interchangeable, you can put blocks under the front wires on the float to raise
the planes incidence. This would be for experimenting. Fly with the blocks, and
once your happy with how it fly's, then bend a new set of wires.

And I strongly suggest to leave the float fairings off for your first flights.

The floats themselves will change the flight characteristics of the plane.
I have found that I fly with allot more rudder to make turns with floats attached.
Which is no big deal, but to ad the fairings too on the first flight... They may act
like large trim tabs, or flaps if not aligned right.

I expect that you will have fun, and soon will be putting floats on more of your planes.
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Old 01-04-2013, 08:28 AM
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Default RE: Houston, I have a problem!!!!

I agree with JRMS that would change the down thrust quite a bit.I have 2 cubs on floats,built both from kits;before paint they were weighed,after they were mounted I indext them to the fus and each other.just a thaught.
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Old 01-04-2013, 10:18 AM
  #45
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Default RE: Houston, I have a problem!!!!

I'll do my best to contribute two  three things.  

First the float plane pilots bible (RCM Cunningham on RC article about setting up floats) - http://www.seaplanesupply.com/chuckcu.pdf

From the article you will learn that correct placement and alignment are only part of the setup.   If the floats don't have enough buoyancy  it will have little chance of leaving the water.   If water comes up to the back of the floats you are probably short on buoyancy.  It's difficult to tell with the alignment issue but you appear to be close to that point (hopefully I'm wrong).  

I just realized one more thing...  Water puts a much more stress on the landing gear wires than wheels or skies (during normal landings ).   Consider some cross bracing to keep the floats from spreading out and some additional bracing to keep the wires from flexing backwards.   Otherwise all that work to align everything will be out the window quickly.   

Flying off the water is fun and totally worth the extra effort.   Just be sure to have an aircraft recover option (boat is best) in case things don't go as planned.  

Carl





 

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Old 01-04-2013, 10:40 AM
  #46
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Default RE: Houston, I have a problem!!!!

That made a bunch of sense to me Fret. Even in my morning grog. After I get a few cups down me I will even re-read it.
JRMS, the angle of the fuse pointing down is about two inches so blocks won't work but I will measure the front and rear wires. And thanks for the tip about the skirts. I have read in passing, very quick passing the side skirts on the swoose has an effect on the flight of the plane. Very quick passing because I have found a few people that have built the plane but not ever had it on floats. It made sense to me but I was never able to get any real answer from anyone. The skirts I have on the LG are almost big but the plane didn't also have the long floats dangling during my trim flights.
Today is another day and I want to float the plane to see how it now sits with the floats in there new position. See if I got rid of that listing problem or not. If so then I will dive into getting the angle of the plane set correctly when on step.
When I lived in the mountains of Calif. I had stock ponds all around me so testing would have been easy. Here all I have are golf course ponds or neighbors SPAs. The HOA people would have a fit if they saw me floating the plane in one of there pools. They have no understanding or sense of humor!!! One of the joys of desert living. The course ponds are cemented and they all have a couple feet drop around the edges, not easy getting a plane in and out of the water.
My hope is to get this plane set up and then have a big rain that will fill the dry lake beds again that I fly from. I'm the only one in the group wishing for rain though. The lake beds do fill up but are only a few inches deep, like 6 to 10 inches. I still have a set of waders from my duck hunting days and thing a flooded lake bed would be a perfect place to maiden this plane. They have been flooded a couple times this year and the ground water table is way up so it doesn't take a lot of rain to flood them again.
First, get it set up right, then start praying for rain!!!!!!!!![8D] Selfish thinking but I need open water!
Both planes were built as float planes because my buddy has a home in Calico on one of the small desert lakes. Just something for two old farts to play with while sitting on a dock having a cold one. He also has a boat and a couple of jet ski's to pick them up if there is a problem. Very cool place and only a couple hours away. Weekend get away. Long story how he managed to get in on buying this house but but there are 5 other people involved and all the cool toys are there for use. Can't wait for summer or an early spring.
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Old 01-04-2013, 11:27 AM
  #47
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Default RE: Houston, I have a problem!!!!

We have no shortage of flooded fields over here at present, if you can find a way for me to send them to you I'll do it willingly.

Long while since I've flown a float plane, but the comments re bouyancy and position of the step are spot on, basically the step needs to be where the main wheels would be on a trike set up, once on step this allows you to rotate and lift off.
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Old 01-04-2013, 12:07 PM
  #48
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Default RE: Houston, I have a problem!!!!

Yes it is a fact I am the worst speller and grammerer in the world! Just poking a little fun didnt mean to sound condesending.
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Old 01-04-2013, 12:42 PM
  #49
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Default RE: Houston, I have a problem!!!!

What happens if you switch the front struts with the back struts?
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Old 01-04-2013, 02:50 PM
  #50
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Default RE: Houston, I have a problem!!!!

If you look you will see a soldered in cross strut so I can't just swap them to find out. I have to just use a ruler and guess. So far today no one with enough water to float it is home so I still don't know if I have the listing problem squared away or not. Once I find out I will start making changes. In the mean time I may start another build and get the last one I did set up with all the gear so when I get the covering I will be ready to go. I seem to be out of a lot of basic supplies like epoxy so a trip to the LHS is still needed.
Once I remove the soldered in cross struts it's easier for me to just bend new wire then to be farting around with what I have. I was once a dental lab tech and wire bending was one of the things I did, just a lot thinner wire!! It's still warm enough to float it so I will make a few more phone calls now and see if anyone is home. It's Vegas, what could these people possibly be doing???
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