BD-5 Information Memo - No. 13

Flight Test Program

The basic flight tests are now completed with N501BD with both the long and short wings. Recent test activity has centered around our new nose landing gear. While the fiberglass nose gear we had was acceptable, it had relatively low dampening which could result in the aircraft porpoising in large bumps or dips in a rough runway.

In keeping with our ground rule of perfecting each component of the aircraft so the finished product will have no undesirable characteristics, we have developed an air-oleo strut that still allows a free-swivel nosegear with no requirement for a viscous shimmy damper. The nose gear was optimized during a great number of high-speed taxi and liftoff runs down an uneven runway surface. We varied strut pressure, strut damping, strut height and angle until the perfect combination was obtained.

The little "Micro" now takes the bumps with ease. The ride is comparable to an aircraft weighing ten times its gross weight.

Structural Testing

Development of the BD-5 has included structural proof-load tests to assure that each component met rigorous strength requirements. The BD-5's structure exceeds the FAA requirements for certification in all areas. Major static load test areas included the fuselage, the wing, the horizontal and vertical tail, the flaps and all control surfaces. The landing gear was developed to withstand a 600 FPM rate of sink landing at gross weight. Over 100 drop tests were conducted during the landing gear development.

Another good example is the design of the horizontal tail. This was designed to withstand full aft stick deflection at maneuvering speed for the short wing configuration, which is a load equal to twice that required to pull 8 G's! With a safety factor of 1.5, this required an 1800 lb. load on the horizontal tail -- almost three times the gross weight of the airplane!

Flutter Testing

The geometric shape and high strength of the BD-5 result in a very rigid structure which is very beneficial from a flutter standpoint. To assure a flutter-free airframe, Bede Aircraft employed an outside consultant service to conduct ground vibration tests and a computerized flutter analysis.

The results of this analysis show that the BD-5 is free from flutter throughout its flight envelope and, in fact, has a much greater margin of safety for flutter than the average certified aircraft.

BD-5 Mailing List To Be Updated

With Information Memo No. 12 we mailed a Questionnaire to everyone, the intention being that the people who returned the Questionnaire to us would be included in our mailing list and would continue to receive Memos and other mailings. Several thousand were sent back to us, and those persons who took the trouble to do this can be assured they will still receive our mailings.

However, the last Information Memo was mailed at Bulk Rate. The result was about 5,000 envelopes were returned to us by the Post Office showing that this number of people had changed their residence. This meant we had to correct 5,000 mailing address cards in our mailing system so as to insure that everybody would receive this latest Memo (despite the fact that the people concerned didn't notify us of their change of address.)

There are several likely reasons why someone might not notify us when they move, but so far as it concerns our mailing list we have now reached a point where we have to be certain that they Information Memos we publish are really wanted by everyone we mail to. For this reason we want to give everyone a chance to notify us if they want to remain on our mailing list.

If you have sent back the Questionnaire to us, there is no need to confirm your interest. You will automatically be on our new mailing list. If you did not receive a Questionnaire, or did not notify us of your change of address but still want to be on our mailing list -- drop us a card or note.

Notify our Cleveland office:

Bede Aircraft, Inc., 355 Richmond Rd., Cleveland, OH 44143

...as this is where our mailing list is maintained.

(Please not that our Memo mailing list at our Cleveland Office is completely separate from our Customer Records at our Newton, Kansas office.)

BD-5 Movie Available

A Super-8mm, four-minute movie of the BD-5 in flight is available from our Newton, Kansas office at $4.50 per copy, postpaid. Send check or money order to BD-5 Movie, PO Box 706, Newton, Kansas 67114.

<pics: An entire page of construction pics of the BD-5 cover page 2 and about one third of page 3. No captions are included with the pictures.>

Flying The BD-5, Part III

by Les Berven, Chief Test Pilot

Since the last newsletter, we have flown the short wings for about 4 hours and have enough data to define both the performance and flying qualities of the production aircraft.

I think the best way to summarize the takeoff and climb performance of the 40 HP short wing is "adequate." Rate of climb is 600-700 FPM at sea level (which is equivalent to most lightplane trainers) and a guaranteed top speed of 195 MPH. With further testing, however, we expect just over 200 MPH, which is outstanding for 40 HP. As soon as we consider the 55 HP or 70 HP engines, however, we have to term the performance as "great" and "spectacular," respectively. The 40 HP, and with a low aspect ratio, as well as higher wing loading, combine to give a rather rapid speed bleed-off with load factor. At full throttle the 40 HP short wing airplane can only maintain 1.8 G's in a level turn at sea level without losing airspeed. The 40 HP long wing, on the other hand, will maintain 2.8 G's.

A complete performance description of all the versions of the BD-5 (based on flight test data) will be included in the new information portfolio to be published soon, and I think it will be apparent that 40 HP short wing is not in the same league as the other versions of the BD-5. If you're interested in aerobatics I would recommend a minimum of 55 HP with the short wings.

Flying qualities, on the other hand, are something else again. I have never had as much fun as I did with N501BD with the short wings. The ratio of tail area to wing area is larger than with the long wings and the stability in all three axis is better. There is absolutely no tendency for the nose to oscillate or wander in rough air and even with the rudder free the aircraft will track straight in light to moderate turbulence. There is no noticeable Dutch roll mode and the spiral stability is neutral up to 50° of bank.

The maneuvering stick force gradient is 3 lb./G (equivalent to 6 lb./G for a center stick), which is optimum for a highly maneuverable aircraft, and stabilizer, aileron and rudder forces are perfectly harmonized.

Roll performance is something to behold; the peak roll rate measured with N501BD at 150 MPH IAS was over 200 degrees/sec! From the initiation of a 360° aileron roll to a wings-level recovery took only 2 seconds. Since roll rate is proportional to IAS, with 70 HP at about 250 MPH IAS, roll rates should be up to around 300 degrees/sec, which is precisely twice the roll performance of a P-51.

Consecutive rolls are easy, and the roll rate is so high there is hardly any need to pull the nose up for entry.

There is really no way to fully explain or describe how this airplane feels to the pilot. The combination of side stick and the outstanding flying qualities combine to produce an unforgettable sensation of perfection. All I can say is that any amount of waiting, working and hoping will be rewarded beyond your wildest expectations.

Tools Now Available

We are still obtaining as many of the required tools as possible for use in construction of a BD-5. The following are now readily available from our warehouse in Newton, Kansas:

Package of 50 1/8" Clecos, $20.00

Package of 50 3/32" Clecos, $20.00

Cleco Pliers, $3.95

*Dimple Dies, $4.75

Richline Model 400 Rivet Puller, $12.00

We will advise our customers when more tools are available.

Ordering Instructions: All tools will be shipped on receipt of prepaid orders only. We regret we cannot ship COD or send anyone an invoice. Our account department is already overworked, and we are just not setup to handle anything but prepaid orders. Orders received prepaid will be shipped out immediately.

*Special Note: Dimple Dies are made on an automatic machine, and then heat-treated. Some hand polishing may be necessary for a smooth finish on the die faces.

New BD-5 Information Portfolio

We are preparing a new and updated information portfolio on the BD-5. It will contain complete performance data on the aircraft, based on actual flight tests. Also included will be latest photos and structural information, as well as a large illustrated "inboard profile" drawing (showing control system, etc.)

Job Opportunity

We have a number of openings in our continually growing prototype shop for highly qualified and fully skilled aircraft mechanics. Applicants must already have homebuilding experience and be skilled in all areas of metal fabrication and assembly, welding, etc. Good pay and other company benefits go along with this rare opportunity to join an enthusiastic team on advanced aircraft development work. Contact: Cecil Buse, Personnel Manager, Bede Aircraft Inc., PO Box 706, Newton, Kansas 67114.

Flight Test Performance Data

Our new information portfolio will contain complete performance data based on flight tests. The following tables list some of the new data.

(The above data is guaranteed in respect of tests carried out with the BD-5 N501BD. However, some improvements may be expected in certain areas after further flight testing with the BD-5 that is now being built as per plans, as which represents the final design of the aircraft. This particular model is now nearing completion.)

Last Update: 5/26/97
Web Author: Juan Jiménez
Copyright © 1997 by Juan Jiménez - ALL RIGHTS RESERVED