symmetrical airfoil cargo pod
 

I have been wanting to fabricate a symmetrical airfoil as a cargo pod mounted to the belly of my 9a. It looks like the pod could be 48" long x 12" thick x 18 " at it widest point which would be appx. 15" back. I have found a company that can hot wire cnc cut a Styrofoam mold. Planning to build out of fiberglass. If anyone has info that could help it would be appreciated. I am familiar with the motorcycle pod for a 10 and the underwing pods plans on aircraft spruce. Has anyone mounted a bellypod like this on their 9/7/6?

Thanks,

Ryan

Get a copy of "Making Fiberglass Molds" with Mike Arnold. It's part of the AR-5 series and covers making a wing-mounted cargo pod that's similar. It covers the techniques well.

Dave

Hi Ryan,

I noticed that you stated 'symmetrical airfoil'... Is that your intent? Adding an exposed airfoil under your fuse will alter the aerodynamic characteristics more than you probably want for a cargo pod. You want to minimize alpha/beta effects of any body you attach.

Of course... I could be totally misinterpreting your post...and if so, ignore the rest....

The motorcycle pod you mention is a half-streamline body extension off of the bottom of the fuselage with no gap. This shape also alters the yaw characteristics of the plane a bit.

Take a look at other fuselage pods that are underslung on other aircraft and note their position wrt CG.

Have a look at a copy of S.F Hoerner's Fluid-Dynamic Lift & Drag books if you can get a hold of them...They were written quite a while ago, but aerodynamic principles haven't changed too much over the years! :)



Good luck!

I installed four 1/4" platenuts to the keel angles under the pilot's seat of my RV-8. These held an Aero muffler under the fuselage when I was running the rotary engine.
Now I'm considering using them to hold up a few ideas, like:
1) an auxiliary fuel tank, https://www.youtube.com/watch?v=a9_TqOB6_Jk
2) a cargo pod or
3) the very interesting Vetterman speed fairing.
http://www.vettermanexhaust.com/ Scroll to bottom of link to read about it.
2&3 above could be the same item if cleverly executed..?

Cargo Pod
 

What about adding a cargo pod like they do on King Airs?
http://www.commuterair.com/commercia...d-baggage-area

My experience on the King Air 100s is about a 5kt reduction in cruise speed and no noticeable reduction in climb. They do seem a bit draggier compared to bare airframes on descent, but that's only when riding the redline airspeed.

the King Air 500 Cubic foot pod requires dual aft fuselage strakes for stability? Interesting design. It seems a cargo pod on an RV would be pretty small to keep it in proportion with the rest of the plane.

Cargopod
 

Look at the cargo pods used on the. 182, 206, Grand Caravan....no aft fins as described for the King airs. I saw onced someone actually designing a boat that will fit in the belly..if im not mistaken it was a high wing like a Husky...i might be wrong.

I have seen several Cessnas with belly pods, smallest being a C185. They are very common on the Caravans. Nobody seems to complain about them (for whatever that's worth). Never flown any of them, so have no experience about performance or handling.

I would think that a well designed belly pod for an RV would be able to fit 2 or 3 small duffle bags. Locate it right in the middle of the CofG envelope and no issues with that either. Probably the best model from the certified world would be the 185.

Check out the cargo pod available as an option for the Glasair Sportsman. 250lb capacity, 15 cubic feet of storage. The hit on cruise speed isn't too big, either.

A good article on a pod-equipped Sportsman here:
http://generalaviationnews.com/2013/...ountry-beauty/

Would be good to have a cargo pod. 👍

Nice accessory. Helpful to haul camping gear, clubs, snowboards etc.

Do a search for helicopter cargo pods. Lots of samples.

Good luck Gents. 😎

Documentation Requirements
 

Can anyone add to this thread or point to another that may give advise on the flight test and paperwork required to fly a pod on experimental? I assume you put in a logbook entry to put the plane back into Phase 1. How much testing is required (Hours/maneuvers/CGs). It almost seems like you should redo a lot of testing and add it to the POH to really characterize the flying quality change. What would the FAA consider sufficient? What would insurance company consider sufficient (in case of an incident)?

Assuming you have the latest version of operating limitations, they call for a minimum of 5 hrs of phase I testing for any modification. I stress the minimum because it's up to the designer of the mod to determine the amount of testing required.

In a case like this, I would recommend a complete range of stall testing at all weights. Also if you have an aerobatic aircraft, I would placard the aircraft for "No Aerobatics with the Pod installed".
You may also want to discuss this with the local FSDO, as they have the authority to require additional testing, as stated in the op lims.

I would have a hard time utilizing a pod. The times I would need it, 2 up, full fuel, full baggage, I am at gross. If I am not, I probably don't need it as I can lower the passenger seat back for more room and baggage.
Does your 9 have enough utility you could accomplish the above and still be under gross enough to utilize a pod?

I see the main benefit of a pod being when the fuel burn moves the cg aft. The front end is pretty light on my 9a.