Keeping the Weight Down.

[Bcone1381]

I am at the starting point of building a Patrol, and I want mine to be simple and light weight. Are there any secrets and techniques that Bob, or others use to keep the weight down without sacrificing integrity?

Bob's Patrol weighs around 950 pounds sets a benchmark for me. I know his is very simple, I assume no starter, no alternator, no battery. Most Patrols I see weight around 150 pounds more than that.

I understand that choices made regarding engines, exhaust, electrical systems, Batteries, fabric covering, propellers, tire size, and paint affect the weight of the aircraft. I would hope that when I compare my raw wing and fuselage to others, that it would be judge by the scale favorably.

Cub Crafters has a saying "Every Gram has a Purpose". So where does it make sense to safely shave off ounces.

[geraldmorrissey]

It's more an attitude then anything else. During the building process ample opportunities will arise where a gram can be saved by doing that extra little bit. Shaping parts to net size without adding extra meat, bolts the right size, just enough primer. Not installing stuff like landing lights, paint on the wings, heavy upholstery, steam qages, heavy floorboards, aux tanks. constant speed props, heated pitot, sound proofing, big engines etc helps. I will be on the light side but will have a simple electrical system and comfortable seats, I'm too old to prop a Lycoming. Fits my mission and I fly in the NW where the weather is crappy much of the time (like today). It doesn't take much to make me happy. Your mission will vary.
Good Luck
Gerry
Patrol #30 Wings

[sjt]

The plans do not suggest that there might be weight savings - at least I have never taken away anything. The pictures are from Bob's patrol. I do not see anything on his panel that is extra.

I think building faster by making it as close to the plans as possible will meet your goal of weight. The trick is to resist adding something you do not need.

If you live near Texas there is a STOL competition in Llano April 10,11

http://www.texasstolroundup.org/

I think Bob is suppose to be there or possibly at Mark's place in Bastrop April 12

[kestrel]

I do not see anything on his panel that is extra.

That looks like a manifold pressure gauge in the middle. That would be extra. ;-)

[Bcone1381]

I really like Bob's bent on simplicity.

Gerry, tell me about the plans you have for your electrical system, and it s weight. What do you mean by a simple electrical system. In 1946, a simple electrical system on a C-14 added about 100lbs. I know there are lighter weight componants now...just wondering what is out there and best practices for day VFR.

I have fond memories of hand propping. It's really satisfying when the engine catches and the C-65 idles obediently at 700rpm. But I want to feel really comfortable flying it solo...and geez, I just wonder about the wisdom of the solo Hand Prop, even though it's chalked, and tail tied down. And yes, an o-320 will be a different beast...plus I am 50 now, and I'll be older when it's flying...so I am talking myself into at least a Starter and Battery.

Keep the feed back coming.

Brooks

[geraldmorrissey]

Hi Brooks, I too have fond memories of propping airplanes. The plane I have now is the first one I've owned with a starter. I have considered just a starter and battery with no generator and may go that way but I am reconsidering a heated pitot for NW flying. No electrical system is really simple, battery, alternator, starter, bus, wiring on and on. See Eric's post on his electrical system. He may have hit the sweet spot. Mine will probably be some variation of his. As I get older during the build process, I think I may have made the wrong decision building a Patrol and should have gone with a LSA but the design was not available when I started. I can still prop a 0-200 but a 0-320 may be beyond me in a few years. Age changed my mission but I am still excited with the prospects of an airplane like the Patrol. It's way more airplane then anything I've ever owned plus it's been fun to build.
Cheers
Gerry
Patrol #30

[kestrel]

Heated pitot... and no attitude instruments?! I'm pretty sure that in a bind I'd want attitude instruments long before I need airspeed. Heck, if you are really getting ice, your stall speed goes up and you don't know what it is even if you have an airspeed indicator.

[Bcone1381]

Gerry, the Patrol is a reasonable LSA candidate if it's kept light. Bob's I think had an O-360 with a constant speed prop and came in about 950. I am not familiar with the electical on Eric Newtons Patrol. Where is the post about it?

[Chewie]

Heated pitot... and no attitude instruments?! I'm pretty sure that in a bind I'd want attitude instruments long before I need airspeed. Heck, if you are really getting ice, your stall speed goes up and you don't know what it is even if you have an airspeed indicator.

I'm thinking of an AoA for that reason, although that would probably freeze up too!

Eric's post on life before and after electrical:
http://bearhawkforums.com/forum/bear...ctricity-weigh

Edit: What wing skin thickness was Bob's 950 Patrol based on?

[kestrel]

I have a friend with a DR107 One Design. It is powered by an O-360. He installed one of the Lithium Iron Phosphate batteries and very successfully runs without an alternator.



--
Bearhawk

[kestrel]

I'm thinking of an AoA for that reason, although that would probably freeze up too!

...and even if it doesn't ice up, it won't tell you when the wing will stall. Stall angle can be dramatically reduced by ice.

- stay out of the ice in these planes.
- get out of the ice if you get in it.
- keep your speed up!
- don't use flaps.

I'd still prefer attitude instruments to pitot heat. Any of the inexpensive EFIS systems would work well. Many even have battery backup.

...and some can provide AoA and work with heated pitot tubes. ;-)

Cheers!
Ty



--
Bearhawk

[Bcone1381]

Mark,

The Patrol Plans call for a skin thickness of .032 in board of the Fuel Tank, .025 over the fuel tank, and .020 outboard of the fuel tank. I assume Bob used these materials on his.

[Chewie]

I read somewhere that Bob tried .016 where the plans now call for .020 but he found it wouldn't hold a shape well and was hard to work with.
-Mark

[kestrel]

He did something like that on the LSA. I've not heard the same for the Patrol.

[Battson]

Here are my thoughts.:

Don't use steam gauges One of them weighs more than my entire EMS panel...

But if you still want to avoid a big heavy electrical things like alternator and battery, then still consider using a tiny little 15A alternator and Li-ion battery They weigh next to nothing. No point having a 2016 vintage aircraft, with worse than 1916 vintage instrumentation. It will cost you big money, when you can't spot your engine failing on one cylinder, or can't run LOP.

Cutting 100 tiny corners on build quality, like using under-size screws or skipping every second nut-plate, wont add up to save you 20lbs... But having no paint, or no solid interior panels, or no auto-pilot could save you 20lbs EACH...

Weight of little nice-to-have things will add up, but some things are worth the weight..... e.g. 0.5lb of door seals and window seals made all the difference for my wife in winter. Now we fly a lot more often in winter, which is a thousand times more valuable, than taking off using 4 inches less runway!

Just my 2c, not all will agree.

P.s. The Patrol with a lower hp engine should be a good candidate for a fixed pitch composite prop. That'll save weight big time.