RE: Yet another Sig Something Extra Build

RE: Yet another Sig Something Extra Build
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RE: Yet another Sig Something Extra Build - 1/21/2008 5:25:26 PM

N1EDM

Posts: 1901
Joined: 7/19/2002
From: Brockton, MA, USA
Status: offline

I wish I had grabbed a set of carbon fiber gear from Fiber-Lite when they were still in production. I just checked and saw that they were not producing them any more.

Paul, I seem to recall that Jimmy at the Field had a SSE with the same Du-Bro gear you are planning to use. Not to sound critical, but I use that same gear on my LT-40 (ahem, perhaps I should say 'used to use'

). I like the gear, but they're kind of heavy. I was wondering if Jimmy could recollect how the airplane acted in an aileron roll with that gear on.

Also, stay on my case. I might have a set of the gear that somegeek is talking about. If I have them in my stash, you can have them. Just don't let me forget!

Bob

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Post #: 76

RE: Yet another Sig Something Extra Build - 1/21/2008 7:33:11 PM

iron eagel

Posts: 1267
Joined: 7/15/2004
From: Middleboro, MA, USA
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quote:

ORIGINAL: alex7403

Why do you guys like cowls so much, IMO it adds complexity and source of issues…
My TT trainer had a cowl, I damaged it all the time until there was nothing to glue anymore then I started enjoying flying the plane, it was ugly tough.
I like sigs because of those cheeks.

Paul,

Regarding the weight removal I have the opposite problem, I’m adding weight in form of reinforcements that not always needed.

you have a big motor and its possible to get a bigger motor why are you trying to remove weight all the time?
In my midstar take off happened as soon as ¾ throttle was reached, no need to remove weight.

Alex,
There are many others that are far more qualified to answer your questions on RCU than myself, BMatthews, CaffeenMan, Dick Hanson, Da Rock to name a few but I will take a shot at it.
As Somegeek said regarding the cowl because it looks good is one reason, my SSE will not look like the others at my field. The other reason is the improved aerodynamics; it will reduce the drag on the airframe by reducing the high pressure areas at the front of the plane, and allowing a less turbulent (cleaner) undisturbed airflow along and around the fuselage. In my case there is also the fact that I am looking to increase the side area of the fuselage to improve the knife edge performance of the airplane. Others have tried adding side force generators, increasing fin and rudder area with success but this is the route I chose to take. Yes it is a bit more complicated and probably more of a PIA than not having a cowl but I feel the improved performance more than makes up for the complication to the plane it adds.
Now as far as the weight yes it is nitpicking but as Somegeek said it keeps the wing loading lower. As you increase the weight and wing loading of an airplane you decrease its performance. The increased weight increases the stall speed and decreases the stall angle, simply put the airplane will stall easier. But that is not all, as you add weight you are calling on the wing to produce more lift, and when the wing produces more lift it also produces more drag, which requires more power to keep the airspeed up. Granted you can add an even larger engine for more power but you add more weight, need more lift produce more drag in a vicious circle. By keeping the weight down you are actually reducing the horsepower needed to perform lowering the power requirements and thereby effectively adding available horsepower, simply by reducing the amount of power needed.
Not to mention since F=M*V by keeping it lighter it hits the ground with less force and the plane will be damaged less.

Regards,
Paul

< Message edited by iron eagel -- 1/21/2008 9:12:12 PM >

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The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

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Post #: 77

RE: Yet another Sig Something Extra Build - 1/21/2008 7:41:18 PM

iron eagel

Posts: 1267
Joined: 7/15/2004
From: Middleboro, MA, USA
Status: offline

quote:

ORIGINAL: N1EDM

I wish I had grabbed a set of carbon fiber gear from Fiber-Lite when they were still in production. I just checked and saw that they were not producing them any more.

Paul, I seem to recall that Jimmy at the Field had a SSE with the same Du-Bro gear you are planning to use. Not to sound critical, but I use that same gear on my LT-40 (ahem, perhaps I should say 'used to use' ). I like the gear, but they're kind of heavy. I was wondering if Jimmy could recollect how the airplane acted in an aileron roll with that gear on.

Also, stay on my case. I might have a set of the gear that somegeek is talking about. If I have them in my stash, you can have them. Just don't let me forget!

Bob

HI Bob,
I got the gear because they where what was at the LHS, yes they do seem a bit heavy and it does bother me a bit how it may affect the roll response. But I am hard on LG and thought they may be more robust and better to take some of my "harder" landings. I'll chase you about those gear now that you offered. If worse comes to worse I may order up a set of the TNT gear I have read about, I think they also offer carbon fiber version also but if I recall right they are around $30... hmm perhaps worth it given my goal regarding the weight of the plane.

_____________________________

The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

(in reply to N1EDM)

Post #: 78

RE: Yet another Sig Something Extra Build - 1/21/2008 8:30:18 PM

alex7403

Posts: 649
Joined: 6/29/2004
From: New york, NY, USA
Status: offline

Thanks Paul I didn’t think about the wing loading ratio.
Just most of my delays happening when I’m doing things out of the manual and then trying to figure out how to resolve these mods.

Regards
Alex

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Post #: 79

RE: Yet another Sig Something Extra Build - 1/21/2008 9:10:27 PM

iron eagel

Posts: 1267
Joined: 7/15/2004
From: Middleboro, MA, USA
Status: offline

quote:

ORIGINAL: alex7403

Just most of my delays happening when I’m doing things out of the manual and then trying to figure out how to resolve these mods.

Same here

The biggest thing for me as far as the building of this plane, is the fact that I am going to fully sheath the wings and fuselage, add more servos for the flap option and all the weight that would add. So I have to try to trim as much weight as possible from the build ,whenever I can, to make up for the weight that those mods add. The other thing I am trying to do is to improve my building skills and techniques so I can build a plane that is lightweight and strong as possible. Probably the hardest part of this build in particular, is trying to improve on what is an already good design, without trashing the performance.
Add to that I want this plane to be a multi purpose platform, so I can use it to carry a video or camera, use it for bomb drop perhaps, and have a very aerobatic fun fly plane as well.

_____________________________

The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

(in reply to alex7403)

Post #: 80

RE: Yet another Sig Something Extra Build - 1/22/2008 2:50:49 AM

KCJarman

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Joined: 8/29/2007
From: Noblesville, IN, USA
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Man, my SSE when finished weighed in at 5lbs 7oz.

I really tried to keep the weight down too. I'm at 20 oz./ft wing loading.

She still fly's like a dream though!!!

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Post #: 81

RE: Yet another Sig Something Extra Build - 1/22/2008 5:37:10 AM

somegeek

Posts: 2084
Joined: 8/1/2005
From: Vancouver, WA, USA
Status: offline

Mine SSE is 5lbs 9oz - this was with the following added...
sheeted turtle deck
custom engine cowl
Added 1/4" to ailerons
Added 1/4" to elevator
Added 1" to rudder
Carbon fiber control rods for rudder/elevator
Aluminum spinner
Exhaust deflector

This is with a AA 4.8V pack which could have been replaced with a 750mah nimh AAA pack to save a few ounces... as well as a throttle servo replacement from standard to say an HS-81.

somegeek

somegeek

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Post #: 82

RE: Yet another Sig Something Extra Build - 1/22/2008 4:22:27 PM

iron eagel

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From: Middleboro, MA, USA
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I have seen SSE weigh in at upwards of 7 pounds fly, and do so fairly well with large engines, they would land a bit hot but perform well. Mine is going to be fully sheathed, added flaps, true turn spinner, full cowl and cooling duct, so I know that will add a bit of weight, that is why I am trying to trim every little bit I can as I build. I know my goal of 4 to 4.5 pounds may be hard to hit but the closer I get to it the better. I have got to beef up the area behind the firewall up to F2 because I can not use the tank floor because of the inverted engine setup I am using. So at least I am going to lose the weight of the plywood that is normally there, and I know the balsa that I will be using as a substitute will be a bit lighter. All of the controls are going to be set u using pull/pull with the exception of the flaps that I will be using control rods on. For the flaps and Ailerons I am going to use HS81 MG servos they are much lighter than standard servos and should compensate for the added pair. The throttle will be setup using a mini servo such as a HS55 more than strong enough for the throttle I used that on several planes without a problem and saves roughly an ounce in weight. I plan to modify the tail group by adding both elevator and rudder area, as well as changing the structure so I can lose the flying wire supports. Now doing all of that and keeping the weight down ought to be entertaining....

_____________________________

The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

(in reply to KCJarman)

Post #: 83

RE: Yet another Sig Something Extra Build - 1/22/2008 10:55:23 PM

KCJarman

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From: Noblesville, IN, USA
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Yes, very entertaining. I will be surprised if yours comes in under 6lbs.

I am watching this build with anticipation. Hope you get all you want from it.

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Post #: 84

RE: Yet another Sig Something Extra Build - 1/23/2008 1:35:22 AM

iron eagel

Posts: 1267
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From: Middleboro, MA, USA
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quote:

ORIGINAL: KCJarman

Yes, very entertaining. I will be surprised if yours comes in under 6lbs. I am watching this build with anticipation. Hope you get all you want from it.

I would be very surprised also!

But I feel that trying my best to maintain my target weight as a goal an try to look seriously at any weight savings that can be gleaned along the way ought to help. Hopefully using a lot of composite materials in the tail feathers will be of some aid. The other thing I have to stay on top of is resisting over doing the structure of the cowl and ductwork. And after weighing the DU-Bro landing gear I have got to look at paying a premium to get some composite gear, they are just to heavy to fit into the plane given the target weight. As I was driving home tonight I thought that I have got to look hard at the fuselage, to see if there are any areas where I can trim the weight there. The first thing that sprang to mind is the canopy hatch structure I know I can do a bit of trimming there. I also have to look and see if I can put the forward part of the fuselage on a diet where I am using the same stressed skin finish as on the wings and tail group perhaps I can trim some lumber there although to be honest I can not see much that I can trim without causing problems with structure. I had originally intended to do the cowl and duct using balsa but I might have to look at making plugs and doing carbon fiber layups for that. Now if I do that, they will have to be bagged so I can keep the weight down, and that would really start to complicate things.

_____________________________

The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

(in reply to KCJarman)

Post #: 85

RE: Yet another Sig Something Extra Build - 1/23/2008 2:40:56 AM

buzzingb

Posts: 1512
Joined: 9/4/2002
From: Bruce, MS, USA
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If you build the SSE heavy at all it won't pull vertical very well, if it is heavy it won't even pull out of a hover unless you use a larger engine like a 61/75. It doesn't take too much to get this plane too heavy. Forget about the extra sheeting, aftermarket tail wheel, etc. and build it as light as possible if you plan on powering with 46. I personally like the plane with a Tower 75 and longer landing gear but most can't understand that so I would recomend to keep it light, very light, and use a 46 with Tower muffler.

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Buzz

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Post #: 86

RE: Yet another Sig Something Extra Build - 1/23/2008 3:37:55 AM

KCJarman

Posts: 176
Joined: 8/29/2007
From: Noblesville, IN, USA
Status: offline

quote:

ORIGINAL: buzzingb

If you build the SSE heavy at all it won't pull vertical very well, if it is heavy it won't even pull out of a hover unless you use a larger engine like a 61/75. It doesn't take too much to get this plane too heavy. Forget about the extra sheeting, aftermarket tail wheel, etc. and build it as light as possible if you plan on powering with 46. I personally like the plane with a Tower 75 and longer landing gear but most can't understand that so I would recomend to keep it light, very light, and use a 46 with Tower muffler.

I'm not sure that you have followed his build thus far........ He's trying something RADICAL!!!!!

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Post #: 87

RE: Yet another Sig Something Extra Build - 1/24/2008 12:08:15 AM

iron eagel

Posts: 1267
Joined: 7/15/2004
From: Middleboro, MA, USA
Status: offline

quote:

ORIGINAL: buzzingb

If you build the SSE heavy at all it won't pull vertical very well, if it is heavy it won't even pull out of a hover unless you use a larger engine like a 61/75. It doesn't take too much to get this plane too heavy. Forget about the extra sheeting, aftermarket tail wheel, etc. and build it as light as possible if you plan on powering with 46. I personally like the plane with a Tower 75 and longer landing gear but most can't understand that so I would recomend to keep it light, very light, and use a 46 with Tower muffler.

Actually I am trying to keep the weight of the airplane as low as possible. Keeping the weight as close as possible to four to four and a half pounds. If you read earlier in the thread, I have gone to some lengths to minimize the weight as much as I can.
I am planning to power this with an OS 55, spinning a 12 inch prop, so I intend to use taller gear.
Other than the wing where I used 1/16 sheathing because of the distance between the ribs, I am using 1/32 contest balsa for the sheathing, that will be covered by .2 oz per yard carbon fiber veil (tissue).

_____________________________

The Wrights never crashed, they only had hard landings. I 've had some hard landings myself. AMA EAA AOPA revver #185

(in reply to buzzingb)

Post #: 88

RE: