V numbers

[barbwire]

Has anyone caculated the following V numbers for an A-1B 180?
Vd --min drag
Vg-- best glide
Or do you have a formula to get close. I saw an article one time that gave formulas for such #'s using the more common V #'s given in the Type Certifict Data Sheet. I know I saved it but cannot lay my hand on it now.
Also has anyone made a spread sheet set up for weight and balance on the Husky--- where you just plug #'s?-- I have set one up and will share it but I am sure there are better ones out there and it probably has been discussed in previous threads.

 

[lowlevelops]

I have an Excel spreadsheet for the weight and balance for an A-1B. It is very simple but seems to work. I am at work now, but I will get it to anybody that wants it later on today.

I quit using it because it was scarey!

I just plan on 70 for best glide.....no idea if that is correct or not. Just wanted to have a plan, even if it is wrong!

 

[barbwire]

Thanks Trace. I want to set up an Emergency checklist and think those numbers would be good ones to know.
Your right the Weight and Balance with anybody of size in the backseat and full fuel will scare you.

 

[lowlevelops]

I was thinking I could put an attachment in a post or PM but I can't figure out how. If you want just PM me your email and I will send over to ya.

 

[Scott Musser]

You can attach most types of documents. Just go to the bottom of your post, click on the Manage Attachments button and browse to find your file. The only file type missing that might be helpful is xls which I'll try to add later today.

 

[lowlevelops]

If there are any quirks on this spreadsheet let me know, I will correct them. Just enter your aircraft specifics in the green cells and at the top of the page.

This spreadsheet is basically untested so please use caution and use at your own risk.

I think you can right click the attachment and save to your computer.

Let's see if this works.....

 

[denningte]

Barbwire - I would be cautious taking advice on min drag and best glide. Each Husky is unique enough to warrant getting that on your own. The difference between the three approved props, new wing, old wing, VGs or no, how the ship is rigged, and what footwear she is sporting make a difference. My advice would be to do a little test flying to figure them out. It gives you a good excuse for more air time!

What you are interested in is maximum endurance speed which equates to min VSI sink (steady) and best range speed which is a calculation challenge taking into account where mileage/sink is maximized (again steady state) and requires consideration of the movement of the airmass you are in.

Max EDR will always be a little lower than Max RNG. A look at a total drag chart will explain why but darned if there isn't one of those for the Husky! I think that is by design for reasons of the multitude of configurations possible. You can't expect the factory to test every ship and be responsible for all of the aftermarket mods available.

If you are looking at this for emergency purposes here is another tip. Leave yourself enough decision space to not have to use fine resolution of stuff like this. Fly high and fast when the landing zones are few and far between and know where you can park your airplane in a pinch. It is better to have to stand on rudder to make a landing spot than milk lift to squeak by the obstacles. In all of my experience with this airplane milking yields no milk. The best defense is to know how to drop her into a spot you know will work and hope there are no gopher holes, barbed wire (except in your case I guess!), high tension lines. etc.

I practice a modified "carrier-landing" squash in mine occasionally and that yields the shortest rollout.

In any case the best defense is a well thought out plan and a lot of practice so when you are sucking up seat cushion, the pea-sized part of your brain that is still working will have something to fall back on.

TD

 

[denningte]

Here is another W&B spreadsheet

All you do is place the aircraft empty weight and arm in the top line to configure and then use the white boxes to input data. You can shift the red lines for your particular model. If anybody needs a bigger envelope (floats, A-1C) you can adjust the chart with the "format chart" function in Excel. You can adjust the warnings by inputting your aircraft's max GW and CG limits in the appropriate cells where they appear.

Any questions or problems - let me know.

 

[lowlevelops]

That is a nice spreadsheet TD! Its amazing that your airplane is basically 100 lbs lighter than mine. What year is your Husky? I am thinking of putting an MT on the front, that should help me a little.

What amazes me is the evolution of my spreadsheets as I use them.

 

[barbwire]

Your W&B table works good and plots the point
I just made several up and printed them. Covered most situations I could imagine and will keep in my flight info for reference. Also if I get ramp checked I will have a W&B. --- thanks tom

 

[denningte]

Trace and BW - thanks for the kind words on the WB sheet. My aircraft is a '98 A-1A with any thing not nailed down removed. I have a good instrument panel and the MT makes a big difference in the WB and handling in the flare. I backtracked the WB numbers that came with the aircraft that's the way it comes out. The one I posted is for 8.5s and not bushwheels so that may make a difference.

 

[lowlevelops]

I built my worksheet with the idea of fitting it on a PDA screen and still be readable without an electron microscope or a bunch of scrolling around. On mulitple leg trips calculating W&B on paper for each take off gets to be a PITA, I was hoping little technology would make my life easier.....not just yet though.

TD, have you ever found an occasion in the Husky when your take off CG is OK but you are out of CG on landing?

 

[denningte]

Trace,

To get to the condition you ask about you would have to shift cargo around. A pure fuel burn always shifts the CG forward an inch or so. If you distribute the max weights throughout the cabin per the POH on wheels with an MT, you tickle the aft CG at max GW.

A float-equipped Hartzell 80" aircraft may be able to break the front CG limit, but I am not a floater. I guess that makes me a sinker Mike Vivion or one of the other float-experienced members can tell you more about float configurations and CG.

Basic flight physics prefers an aft CG for better cruise performance so front loading is not a goal for any reason unless there is a more compelling reason than cruise efficiency.

 

[lowlevelops]

TD,

The reason I was asking pertained about your landing CG calculation on your spreadsheet. I suspect in heavy iron there are worries there, but I have never found a situation where I was out at landing in GA aircraft. There is a piece of mind of knowing what to expect when you get there tho.

No offense intended, just wondering is all.

 

[denningte]

Trace,
No offense taken. I was just trying to answer your question as completely as possible given my understanding of the Husky WB situation