SCAT Electronic News 16 July 2001 issue 600
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- Category: Archive 2001
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SCAT Electronic News 16 July 2001 issue 600
Table of Contents
=================
SEN
Transport for bike from NATS to Lost HIlls - Spence
MMM FAI Annual - Phair
HP01-1.1 Flight Summary - Cowley et al
Rangefinders - Brokenspar
Graupner DS281 servo - Van Wallene
F1B turning - Wantzenriether
Thanks
SEN
===
Issue 600 !!
Transport for bike from NATS to Lost HIlls
==========================================
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
I am trying to find someone from the West Coast who is driving to the NATS
at Muncie with the capability to haul a motorcycle back to lost hills.
I will pay for the transport! I have a space reserved in the new storage
facility at Lost HIlls.
Henry Spence
This email address is being protected from spambots. You need JavaScript enabled to view it.
817 473 1673
MMM FAI Annual
==============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Roger,
I want to set the record straight regarding historical performances at the MMM
FAI Annual. It has been reported in two places in SEN that
the max out this year
by George Batiuk was the first in the long history of this contest. With
absolutely no intent to diminish George's performance,
it must be noted that Jim
Bradley, flying F1A, maxed through the entire 14 rounds at the 1988 MMM FAI
Annual. George remains as the first Wakefield flyer to achive this level of
performance. And, over the years, there have been many more competitors in F1B
at the contest than either of the other two events. Flying at 6100 ft elevation
remains a challenge for all F1 classes.
I want to extend my congratulations to George for his achivement, and welcome
him to join Jim Bradley in an elite club of two!
Best Regards
Ken Phair
HP01-1.1 Flight Summary
======================
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Modellers,
* Flight was successful !
________________________________________________________________________
From: Curtin, Bob on Sun, Jul 15, 2001 5:52 AM
Subject: HP01-1.1 Flight Summary
On July 14, 2001, Helios Prototype took off from Pacific Missile Range
Facility (PMRF) at Barking Sands, Kauai, Hawaii, and flew to a peak radar
altitude of 76,271 feet. This was the first high-altitude flight of
AeroVironment's Helios Prototype and was a major milestone for the NASA
ERAST Program. Gross weight for the aircraft was 1618 pounds.
Fantastic still and video shots were gathered from a chase helicopter
during the early phase of the climb. See the attached photo taken by
Nick Galante. The islands of Niihau and Lehua are shown in the photo.
The mobile pilot, throttled-up for take-off at about 8:08 AM HST. The
aircraft took-off into low-altitude turbulence that created a nice show
for approximately 600 spectators.
The flight crews and procedures worked extremely well. After completing
preflight tests that started at 3:15 AM HST the aircraft was ready to
take-off at the planned time of 7:50AM HST, but was delayed by 18 minutes
while Hawaii's trade-winds moved clouds out of the path between the sun
and airplane.
Minimum temperature during the flight was -90 degrees Fahrenheit, at
about 49,000 feet. At peak altitude, the temperature had increased to
-70 degrees (Rawindsonde data). The ground-based radar reported an
altitude peak of 76,271 feet. The system's differential global
positioning system reported the peak altitude at 76,240 feet. The record
set by AeroVironment's Pathfinder Plus in 1998 is 80,201 feet. However,
Helios Prototype's flight is certainly the highest any propeller-driven
aircraft has ever flown on it's first high-altitude flight!
Hundreds of systems worked perfectly during the flight. The
environmental control system worked very well. All avionics and
batteries were kept within their acceptable temperature limits. The
propulsion system worked flawlessly. Data from this flight will allow
the team to optimize the prop pitch slightly before the next flight. The
solar array supplied a peak power of about 30 kW and was still providing
about 24 kW at 5:00 PM HST. The control system collected data on the
stability of the aircraft during more than 40 frequency sweeps done
during the flight. Data was collected at many altitude increments on the
way up in order to clear the low-power envelope for the descent. These
tests reduced the peak altitude, however they will not have to be repeated
during the next flight.
The Helios Prototype made a perfect landing at 2:09 AM HST, in light
winds, on PMRF runway 16 at Barking Sands. The flight duration was 18
hours and 1 minute. The onboard video cameras, including a low-light
camera for night, supplied beautiful footage of the aircraft, sunset, and
landing.
This flight was a major milestone for the NASA ERAST program. The flight
was made possible by the hard work and dedication of the AeroVironment,
NASA, PMRF, ITT, HTS, and Kauai Community College personnel on the flight
team and, the continued support of NASA. The team will look at the data
from this flight carefully to optimize the vehicle for the next, higher
altitude flight. The completion of this flight brings us one step closer
to achieving our milestone of flight over 100,000 feet.
Martyn gave a partial report earlier .....
Modellers,
Still Climbing - thanks to new Andriukov props ! (take-off picture =
enclosed)
[He supplied some very good pictures that anoung other things
show the props - the next thing for F1Bs ?. These will be sent as
attachments in due course]
Rangefinders
============
Author : This email address is being protected from spambots. You need JavaScript enabled to view it.
Anyone have experience with the Leica LRF 800 Ranggemaster...?
Laser rangefinder.
Range, 800 yards, +/- 0.5% accuracy, 7x magnification...
Push a button - the LED gives a reading.
What could be sweeter ?
399.00 USD
( best of everything ) Brokenspar
Graupner DS281 servo
====================
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Hi,
One more unexpected advantage of the new digital Graupner DS281 servo:
A typical problem with modern electronic timers is a microcontroller
reset or so called 'brown out' condition, caused by voltage glitches
(dips) when a servo starts to move. Such brown outs can be the cause of
all kinds of strange timer behaviour like DT at launch for instance (!)
Timer developers are using all kinds of tricks to keep the risk of a
brown out condition to a minimum such as:
-high capacity buffer capacitors over power supply
-moving servos in sequence instead of simultaneously
-Use of low internal resistance NiCads (Sanyo)
During recent tests I discovered that the new DS281 causes far less deep
glitches than comparable analog servos.
I use a voltage booster (transforms any input tension up to 5.5 V) in
my timers, and the minimum voltage at which the timer works without
brown outs caused by servo movement (using one servo) is:
2 Volt using the new digital DS281
4 Volt using an old comparable analog servo
It would appear that Graupner implemented some kind of system to avoid
strong current rush when starting servo movement.
regards, Allard
F1B turning
===========
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A few months ago, on SEN was posed a question about the turn of a climbing
F1B : why does the model sometimes go straight or to the left, after ten or
fifteen seconds of flight ? Some assumptions were delivered on SEN, but the
problem is not solved entirety, it seems. Here a new contribution. Walter
Eggiman, of Switzerland, made interesting observations in connection with
his four models, whose plans are published in "-Thermiksense"- 2/20
01.
On the dihedral pannels, Walter makes his profile decrease very clearly in
camber. The tip profile has only 1 or 1.5 millimetre undercamber. The
thickness is smaller too. Observation made after this modification : after
the 4 seconds VIT, the model does not plunge to the right, as it is almost
obligatory. Moreover, for the glide, at the time of the entry in thermals,
there is no more a brutal tightening, but a progressive change of the curve.
The glide turning can be trimmed on a definitely larger radius.
This improved reaction in yaw is coupled with a fin profile having a very
round leading edge, a kind of Woebbeking's stabilizer airfoil. The lift
slope gradient of the fin becomes smaller. One needs 4 degrees of
autorudder, whereas an usual profile requires two degrees. This allows a
finer adjustment of the climb beginning. The sidethrust is of 2 to 2.5
degrees, which ensures a tighter turn at the smallest deceleration of the
model.
Perhaps the most beautiful will be this: there is no wing wiggler - Walte
r
writes : "-In direct comparison with my 'WW colleagues', until now I never
had the impression that I had need for that. "- The wing dihedral is as
usual : 110 to 120 millimetres, and the wing weights 59 g or so.
----
Jean Wantzenriether E-mail This email address is being protected from spambots. You need JavaScript enabled to view it.
Thanks
======
Thanks to Bob Van Nest for his donation in support of SEN
..................
Roger Morrell
