During the development of the CF-105, AVRO & the Canadian government needed performance data, particularly for drag at supersonic speeds, for the selected design configuration. This information was difficult to obtain due to a shortage of high speed wind tunnels & calibration problems with them due to the interaction of the model support inside the tunnel.
NACA (later NASA), developed a technique at Wallops Island VA, using a Nike Booster to bring an aircraft model up to supersonic speed, then release it as the booster burned out.
AVRO decided to pursue this approach with the CF-105. The Canadian Armament Research & Development Establishment (CARDE) had a small missile range at Picton Ontario that was established for test firing the Velvet Glove Air to Air missile they were developing.
These were initially ground launched & later air launched from a CF-100 aircraft that operated from RCAF Trenton during the firing trials.
In 1955 the ground firing program & the early aircraft launches of Propulsion & Control vehicles was complete & Guidance trials for the Velvet Glove program were moved to Cold Lake Alberta due to concern in case an errant missile fell on Prince Edward County. This decision was also politically motivated because the RCAF had established a minimal range by moving a Picton Radar to Cold Lake & wished to exploit it. This allowed exclusive use of the Picton Range for AVRO & the CF-105.
What follows is an account of the CF-105 Free Flight Model Testing, as recalled 40 years later by a once young (mid 20's) CARDE Scientific Officer. Readers must excuse the details of the Range instrumentation that are necessary to understand the results, or lack of, that were obtained. When the CF-105 program commenced, the Picton Range at Point Petre shared the range with the Canadian Army School of Artillery & the Lake Ontario Shipping !
Although Notices to Mariners were regularly published ahead of scheduled firings, during the shipping season vessels often came close to Point Petre & ignored the restricted area. This often delayed firings, particularly if a string of boats appeared over the horizon & created practical problems due to the limited life of the missile/model telemetry battery packs. This problem was eliminated in the winter months, but working at the launch pad & camera stations was not a pleasant experience. Fog was also an occasional problem, when the warm summer air encountered the cold water of Lake Ontario.
Relations between the AVRO & CARDE range personnel were always cordial, although there is no doubt, that AVRO personnel were disappointed with the poor results obtained. They were in a difficult position, because they were using the facility of their customer, the DOD. No attempt was made by CARDE to monitor, record or leak the results of the firings.
The actual range extended 22000 yds from Point Petre. The Launch pad was 650 ft in front of the Control Building. This had an upper floor for instrumentation equipment, communications & firing control. The lower floor was for vehicle checkout & assembly. An adjacent Quonset type assembly building next to the magazine was used for mating vehicles to boosters. The launcher was then towed to the Launch Pad. AVRO provided their own launcher which appeared flimsy as shown in pictures taken at the pad but it gave no problems in practice & the actual firings were flawless.
When the program began there were three types of range instrumentation at Picton :
This was S band Instrumentation radar. It was the best available at the time & was a major rework of the WW2 SCR -584. These were the very first tracking radar's, developed in the US as part of a Anti Aircraft system using a battery of 90 mm guns. They were very successful in destroying V 1 Doodlebugs at the end of the war. This radar had an excellent pedestal & angular tracking rates.
Initially they were upgraded to have a 12 ft solid dish in place of the mesh version supplied to the army. They were mounted in a cab. This was the type of radar sent to Cold Lake & referred to above. A later version known as the AN-TPQ 18 was installed at Picton in the main two storied Control building . The radar was installed in the building to improve accessibility for maintenance & to provide a stable platform for the antenna. This radar had cameras mounted on the antenna to record Azimuth, Elevation & Boresight data through a hole in the dish. The antenna cameras & a Range display camera were controlled from an additional rack in the Control room. The signal processing was quite different in this radar, in that the original, J scopes with hand wheels, were actually an extension of a synchro in the range tracking loop & used to manually acquire the target in range prior to selection of automatic tracking. These were replaced by three A scopes & a cursor (strobe) that could be placed on the target prior to selecting automatic tracking.
This 'improvement' had some bearing on the poor radar results obtained for the CF-105 model program as discussed below..
B. Kine Theodolites
This was a four Camera system that had the capability to support 6 cameras. The Cameras were an attempt to copy the excellent German Askania cameras that were used at their ranges during WW II These were essentially 35 mm Cameras that took 5 full sized frames per second. The azimuth & elevation scales were exposed onto each frame with flash tubes. The shutters were venetian blind & used a switch to send a 2 msec pulse back to the control station. By sending a dedicated trigger pulse to each camera shutter & a common flash pulse later, it was possible by adjusting the camera pulses & observing the result on a scope in the control building to synchronize all the camera within 2 msecs. The angular accuracy of the system was quoted as 1 min. The focal length of the folded lens system was 60 cm & the cameras were laid on the target by a single operator using binoculars clamped to the elevation axis.
The cameras were sited, (#1) behind the Launcher & close to the Control Building, (#2), on a point 1 mile from the launch site & looking back towards the launch site, (#3), along the lake shore 3 miles East from the Launch Site & (#4) miles East along the lake shore. Cameras #3 & #4 had no visible line of sight to the launch site.
The standard FM/FM telemetry system was used, with AVRO supplying the model package. They utilized the CARDE ground station. This had dual receivers, multiple discriminators & tape recorders with helical antennas on the roof. After the firing all the records were taken to AVRO for processing & analysis after a 'quick look' at the range.
D. Doppler Radar.
This equipment was purchased using CF-105 funds & installed before the drag models were fired. It was intended to accurately measure the vehicle velocity during boost & at separation. It was a crucial part of the program to allow the drag coefficient to be measured by calibrating the accelerometer for the subsequent free flight portion after separation. This was a C Band system installed on a 90 mm gun mount close to the Control building. Being a CW system it needed the injection of a phase & amplitude adjustable signal to cancel out the primary ground clutter. Once adjusted it was stable but moving the mount caused the clutter to change and it required manual readjustment.
The models were fired over a period of about a year & were of three types. The first group used a simple model configuration to validate the Launcher & Range Instrumentation. The drag models (2 or 3) were superbly built to scale & the primary reason for the model program. These are the models shown on the photographs at the Launch Pad. The cylinder over the nose probe protected the angle of attack indicator & was removed just prior to launch. The Drag Models were interleaved with the Yaw models (2). The Yaw models had a type of gatling gun system that fired a series of 12 ga shotgun cartridges through 1 in dia holes on ea. side of the fuselage below the cockpit to create a step function in yaw both left & right. There were at least 3 shots each side fired at about 2 second intervals. The Yaw models were a similar configuration to the launcher validation models.
All the launches were successful without any hang fires or similar problems.
The early proving flights revealed several serious problems. For these and every subsequent flight the Telemetry performed as predicted & good data was obtained.
The other range data was unsatisfactory as described below :
The radar was only 600 ft from the launcher & within the 'Main bang' or minimum range of the radar. This meant that the target had to be tracked with an optical tracker until acquired by the radar operator while in flight. At that close range, the elevation rate at lift off was very high & the operator could not generally track the target. On one occasion when the target was acquired the separation occurred & the radar tracked the largest target which was the spent booster This was long before the days of Kalman filters or leading edge tracking to smooth the range data.
The radar had the ability to track a transponder (beacon) and an S band transponder was installed in a model with a time delay to place the return outside the main bang & on a different frequency. This time the radar locked on to the reflected return from the launch pad and no data was obtained.
A visit was made to Wallops Island to see how they handled the radar & booster separation problem. Their technique was to use a radar of the AN/MPQ 12 type placed 1 mile from the launcher. This was the same type that was sent to Cold Lake. The operator at Wallops locked on just after take off, then manually forced the servo wheel onto the leading target as the target split into two at separation.
In summary the radar data for the CF -105 models was practically worthless.
2. Kine Theodolites
As stated above the cameras were copies of German Askanias made in England. However the cameras were of poor quality, did not appear to have been tested prior to shipment from the factory & frequently jammed or broke the film during a 'mission'.
In addition two sites, #1 & #2 could not manually track the lift off due to the high elevation rate, plus the targets were small, at long range, & the actual launch was not visible at two stations, so the system was a failure.
This in spite of an intensive effort by both CARDE & AVRO personnel with items such as film selection & painting the models "Dayglow Yellow" to improve visual & photographic observation.
An additional site #5, was established beam on, to the Launch Pad & about a mile away. This used a salvaged German Askania camera which performed perfectly. Unfortunately without a second & preferably a third camera, for a least squares solution very limited trajectory information was obtained.
3. Doppler Radar
Because of the poor radar results the doppler radar was operated with its own optical tracker. It was difficult to maintain signal during the boost phase due to the limited servo capability of the 90 mm Gun mount & elevation rate problems similar to the Radar & Kine #1.
The data obtained was patchy & far below expectations.
It is fair to say that AVRO did everything that could have been asked of them with the free flight model program. CARDE failed, but the problems were mainly due to poor equipment siting, time & money. Certainly there was no lack of interest or enthusiasm amongst the CARDE personnel at Picton.
A good solution would have been to move the launch site 1 mile to the point where Kine 2 was located. This would have required a modest capital investment for concrete pad & assembly building plus the necessary security fence. The doppler radar could have been placed on a mobile carrier, unmanned during the firing, located close to the launcher & elevated at 45 deg. along the projected flight path. A solution like this was handicapped by the lack of time, as the firings commenced shortly after they were announced.
Perhaps the upper management at CARDE in Valcartier PQ knew the range had no future & were unwilling to commit additional funds to a losing cause.
After the model flights were completed an attempt was made to establish a calibration range for speed measurements of the CF-105. Two of the Kines at sites #1 & #4 were elevated to 90 deg & a CF-100 flown over them at about 30,000 ft using the radar and coupled plotting board to steer the aircraft. This provided a 4 mile long precise baseline & several successful runs were made.
AVRO did not follow up on that and the Picton Range closed for lack of work in mid 1957.
Peter Beadle. C.Eng MIEE Oct 25 1998